1. Basically, the only two story progression mods out there are Twallan's Story Progression and the option with Awesomemod to implement an improved story progression. I far, far,
far prefer the latter. It's customizable, not a core mod, and the only thing it does is overhaul story progression, while Awesomemod's progression is part of a much larger core mod. And Awesomemod's supporting forums are the scum of the simming community.
As for which part of Twallan's Story Progression to install (as you can see on
the mod's page, there are a lot of things up for download), you need the base mod for your patch level, and everything else is optional. But let's get to how to install mods first.
2. Mods are easier to install than you think.
I quite like
Jeana's thread on installing mods, but I'll summarize here too (more specifically for Windows, though):
- Go to your Electronic Arts folder, in Documents, and then to The Sims 3's folder.
- Inside of that, create a new folder called Mods.
- Inside of your new Mods folder, create a new folder called Packages.
- Download the Resource.cfg file from here. You can ignore their tips on editing Resource.cfg. I've never needed to edit it.
- Get a reputable program to extract .rar files. Jeana recommends 7-Zip on her thread and I concur. In order to extract Resource.cfg from the .rar, open 7-Zip, find where the .rar is (probably in downloads. On Windows, this is C:\Users\[user]\Downloads), highlight the file, and press "Extract." This will prompt you for an output path. Resource.cfg should be sent to your Mods folder (C:\Users\[user]\Documents\The Sims 3\Mods; again, for Windows).
After Resource.cfg is in it's proper place, get your mod packages into the Packages folder (they usually have to be extracted from .zip/.rar/.7z archives, so keep 7-Zip around) and they should automatically work.
3. Make Factory Reset folders. MoonsAreBlue
has a thread on it, but I'll summarize again.
- Rename your usual The Sims 3 folder in documents, to something else ("The Sims 3 old" or something like that). When you start the game again, it will create a new The Sims 3 folder with nothing in it.
- Fill up the new folder with what you need for challenges/dynasties, keep your mods away from it, and rename it to something else and name your old folder to "The Sims 3" again to make it the one that the game will use.
Feel free to ask more questions if you need to.