first go here, and make copies of your install:
https://www.sas1946.com/main/index.php/topic,19.0.htmlthen get the no CD patch to start them with:
https://www.sas1946.com/main/index.php/topic,1117.0.htmlnow you never have to re-install again. if you ever have to start over, just copy your safety copy of 4.09 and work with the copy.
Make another copy, and update that with the 4.10 and 4.101 pacthes. So youll have both 4.09 and a 4.101 versions.
You can make a spare copy of each of those also. It would be a good idea.
Then you have to decide, do you want to install mods manually one at a time, or do you want a complete one stop sollution?
If you want to go the manual route, then choose the appropriate version fo SAS modact and install it. Also visit the tutorial board and read EVERYTHING there.
SAS Modacts is available for either 4.09 or 4.101 at the moment, and mods are marked by icons for what versions they work for.
If you want a one stop mega pack with everything in, then get UP. At the moment UP is for 4.09 only, the 4.101 version is in the works, and will be here in a month or two.
If you want to install UP in your 4.09 install, then the version of UP you want is 2.01. Visit their forum and grab it.
You can also then if you like, add mods manually on top of that UP install, just grab this
https://www.sas1946.com/main/index.php/topic,7949.0.html and carry on from there.
If you use UP, it already has a modact in, so you dont install ours over it, or it over ours.
but do visit the tutorial foum
https://www.sas1946.com/main/index.php/board,7.0.html and read it all, three times!