Anapanasati with Dhatu Manasikara In Maha-Rahulovada Sutta monk Rahula asks the Buddha for instructions on developing Anapanasati. The Buddha didn't directly give instructions to him of Anapanasaati but instead, gives instructions on developing Anatta on the earth property, the water property, the fire property, the wind property, &amp; the space property.

&quot;Rahula, {any form whatsoever that is past, future, or present; internal or external; blatant or subtle; common or sublime; far or near: every form is to be seen as it actually is with right discernment as: 'This is not mine. This is not my self. This is not what I am.' There are these five properties, Rahula. Which five? The earth property, the water property, the fire property, the wind property, &amp; the space property.&quot;

It also states developing the four Brahma Viharas, the perception of Unattractiveness and Impermanence.
After that only the Buddha gives instructions on Anapanasati.
I also have heard that for the people who are untrained in Anapanasati, they may meditate on the elements and then go to Anapanasati. (Some say it is better to do this way since not doing Anapanasati properly can lead to difficulties in the mind)
PS - I tried the above approach and it was somewhat smoother than directly going into Anapanasati.
Q1. Is doing Dhatu manasikara first and doing Anapanasati afterward a smoother and an effective way of doing Anapanasati?
Q2. Also, can I know the simple explanation of what these actually mean

I will breathe in calming bodily fabrication.
I will breathe in sensitive to rapture.
I will breathe in sensitive to pleasure.
I will breathe in sensitive to mental fabrication
I will breathe in calming mental fabrication.
I will breathe in sensitive to the mind.
I will breathe in satisfying the mind
I will breathe in steadying the mind
I will breathe in releasing the mind
I will breathe in focusing on inconstancy.
I will breathe in focusing on dispassion.
I will breathe in focusing on cessation.
I will breathe in focusing on relinquishment.

What do these mean and how to achieve this is Anapanasati?
Q2. Also, can I know the simple explanation of what these actually mean
  
  
  
  I will breathe in calming bodily fabrication.


This is a mistranslation. It should be 'body fabricator'. The body fabricator is defined in MN 44 as the in &amp; out breathing. 

The breathing is the body fabricator because when the breathing is calm, the body is calm; if the breathing is agitated, the body is stressed.; if the breathing is unhealthy, the body is unhealthy. If the breathing ends, the body dies. If the breathing starts, the body lives. 

This calming the breathing is achieved by having a quiet non-attached mind, which unifies itself with the breathing.    


  I will breathe in sensitive to rapture.


When the breathing &amp; body calm sufficiently, rapture will arise to be the predominant object of meditation. It generally takes at least 60 to 75 minutes of calming the breathing constantly for rapture to arise. 

Remember, the mind must be non-attached &amp; in the present moment rather than craving for results &amp; thinking about the future. 


  I will breathe in sensitive to pleasure.


If the mind remains non-attached &amp; concentrated, the rapture will calm and pleasure or happiness will appear, which is a more refined pleasant feeling than rapture. Rapture (piti) is very vibrant, bubbly, agitating &amp; seductive where as happiness (sukha) is more subtle, calm &amp; soothing. 


  I will breathe in sensitive to mental fabrication


This again is a mistranslation. It should be 'mind fabricator'. Rapture &amp; happiness are the mind fabricator (citta sankhara) because they seduce the mind and, if the mind is not mindful, rapture &amp; happiness will fabricate craving, greed, love, attachment in the mind. This is why they are called the mind fabricator because they fabricate or condition defilment in the mind. 


  I will breathe in calming mental fabrication.


Just like when the breathing is calmed, by remaining non-attached &amp; equanimous towards rapture &amp; happiness, they will calm. 


  I will breathe in sensitive to the mind.


When rapture &amp; happiness cease, the mind-heart (citta) itself becomes the object of meditation. Here, the mind has concentration. The mind is not thinking. 

However, there will be some residual defilements in the mind such as greed, anger &amp; confusion that subtly arose in response to the rapture. For example, sometimes the mind does not like rapture because the rapture disturbed the mind when it was peacefully watching breathing. 

At stage 9, any residual defilements (kilesa) of the mind are observed &amp; calmed. 


  I will breathe in satisfying the mind


When the defilements are calmed, the mind feels joy due to the cleansing of the defilements. This joy are more refined &amp; subtle than rapture &amp; happiness because the mind is now much more pure. 


  I will breathe in steadying the mind


When the joy calms, the mind concentrates deeply, in a one-pointed manner because it is pure. 


  I will breathe in releasing the mind


The mind (automatically) purifies itself of the one-pointedness of concentration &amp; becomes open, bright &amp; perfectly non-attached. 


  I will breathe in focusing on inconstancy.


At the previous stage the mind became liberated, open &amp; non-attached. 

Now, the impermanence of whatever subtle sense objects come to the mind is seen very clearly. 

Here, the impermanence is so predominant that the mind sees mostly impermanence (rather than specific objects of impermanence). It is like watching a movie at very fast speed. 


  I will breathe in focusing on dispassion.


In seeing the crazy impermanence, craving is destroyed more because the impermanence makes sense objects look ugly, unattractive &amp; undesirable. 


  I will breathe in focusing on cessation.


As craving is crushed or suspended, a taste of nirodha/Nibbana/no suffering/perfect peace occurs. 


  I will breathe in focusing on relinquishment.


The mind now fully knows all the experiences &amp; things are not-self. It gives up holding anything as self. 

The above is the fulfillment of stream-entry on the level of neighbourhood concentration. It is not jhana. It might take a few continuous meditation retreats to achieve this if the mind has no hindrances because reaching stage 9 in a very clear way can be difficult. However, one meditation retreat should be enough to reach stage 8 (if there are no hindrances). 

Reading here: Buddhadasa: Mindfulness With Breathing Secrets of Life