What does Buddhism teach about the start and end of world? I always wonder how all this started... How did we arrive here? What are we doing in this place?

So are there teachings in Buddhism that are clear on this point?

How did the world start? and How is it gonna end?
Here is one teaching the Buddha gave on the start of the world:


  Dwelling at Savatthi. There the Blessed One addressed the monks: "I
  will teach you the origination of the world &amp; the ending of the world.
  Listen &amp; pay close attention. I will speak."
  
  "As you say, lord," the monks responded to the Blessed One.
  
  The Blessed One said: "And what is the origination of the world?
  Dependent on the eye &amp; forms there arises eye-consciousness. The
  meeting of the three is contact. From contact as a requisite condition
  comes feeling. From feeling as a requisite condition comes craving.
  From craving as a requisite condition comes clinging/sustenance. From
  clinging/sustenance as a requisite condition comes becoming. From
  becoming as a requisite condition comes birth. From birth as a
  requisite condition, then aging &amp; death, sorrow, lamentation, pain,
  distress, &amp; despair come into play. This is the origination of the
  world.


And in the same teaching the Buddha gave the explanation for the end of the world:


  "And what is the ending of the world? Dependent on the eye &amp; forms
  there arises eye-consciousness. The meeting of the three is contact.
  From contact as a requisite condition comes feeling. From feeling as a
  requisite condition comes craving. Now, from the remainderless
  cessation &amp; fading away of that very craving comes the cessation of
  clinging/sustenance. From the cessation of clinging/sustenance comes
  the cessation of becoming. From the cessation of becoming comes the
  cessation of birth. From the cessation of birth, then aging &amp; death,
  sorrow, lamentation, pain, distress, &amp; despair all cease. Such is the
  cessation of this entire mass of stress &amp; suffering. This is the
  ending of the world.


To understand this I think takes familiarization with the Dharma and specifically the teachings on the Four Noble Truths and dependent origination.