Very Vague and Most will say s4 tuning wiki which is this simplest write up there just about is then take a look at all these translated modules
http://www.nefariousmotorsports.com/wiki/index.php/Main_PageThen take a look back at s4 tuning wiki
Then search a whole lot about particular solutions for particular problems i have found this helps a decent amount
Then read the entire forum... a couple times lol
I am by far a noob at this still but the information is all here wether you use google to search on the forum or the forum search button but answer to your following
1) You might be able to use the 518ak file and just flash and tune that but if your looking to define your 518f bin you need WinOls
https://www.youtube.com/watch?v=0dkuoFh2foQ This video will help
2)This is all in s4 tuning wiki that is a great general guide line for the me7.5 also
3)again S4 tuning wiki, look at other stage 1 or 2 tunes, search a little more
I can help with what I know personally
GET A BOOT MODE HARNESS AND GALLETTO