Disabling SIP on a mid 2012 Mac Running Sierra 10.12.16 I tried booting my mid 2012 mac (which is running Sierra 10.12.6) in recovery mode and opening the terminal; I would like to disable SIP. As per usual, I typed "csrutil disable", and 'command not found' was returned. I looked at klanomath's answer here (csrutil: command not found) though I didn't quite understand what he/she meant by 'booting to your main volume'. I am not sure if that is relevant here, but I am inquiring if there is any further way to disable SIP. Is high-sierra needed or helpful here? 

(Also, if possible, an answer comprehensible by someone with very little background in computing or working with the terminal would be highly appreciated)

Thanks in advance.
Instead of just writing "csrutil", replace that with:

/Volumes/Macintosh\ HD/usr/bin/csrutil


so the whole thing becomes:

/Volumes/Macintosh\ HD/usr/bin/csrutil disable


Note that "Macintosh HD" should be replaced with the name of your startup disk. If you do not know the name, then run the following command:

ls /Volumes


It will list the available volumes for you.

If the above gives the error message: "Operation not supported" it means that your recovery system is a version so old that it hasn't got support for the functionality necessary to run csrutil.

In that case try starting up in Internet Recovery mode by holding down Cmd-Opt-R while booting the Mac, which means that the files for the recovery system are downloaded adhoc from Apple's servers. This should give you a version new enough to run csrutil. 

In case that is not possible then you could instead upgrade your own recovery partition to a newer version or alternatively create a recovery partition on a USB pen-drive and boot on that. How to do both is described here:

https://superuser.com/questions/1024493/updating-recovery-partition-in-os-x-el-capitan