Installing add-ons for TS2012

I am a noob to TS2012, I used MSTS for several years until leaving it back in 2005 when the VR I was a member of closed up shop. This week, I ended up purchasing TS2012 w/HC expansion and immediately added the NEC/Acela/Genesis expansion. My question here is probably simple, but I am here scratching my head.
I purchased the above mentioned products via Steam, but there are many freeware/donationware add-ons I am wanting to add. Okay, here comes the stupid part, how do I implement the downloads into the Steam version of TS2012?
I realize it must be a very simple, almost "plug and play" process, but I want to be sure.
Back in the MSTS days, I would fuss and cuss when I spent hours downloading routes and equipment and once I installed via directions, it wasn't there.
Now I am not an idiot when it comes to DL/Installing of products, I just want to be 100% educated and informed when it comes to adding routes, scenery, equipment, etc. to TS2012. From my experiences with MSFS over the years and operating a VA, I always found that the add-ons for Flight Sim were always more user friendly and almost "idiot proof" when it came to installing. It seems with Steam, it may be just a little difficult to perform these additional installations.
Thanks in advance for your assistance, and please, don't laugh too hard at me and my apparent idiocy!


I purchased the above mentioned products via Steam, but there are many freeware/donationware add-ons I am wanting to add. Okay, here comes the stupid part, how do I implement the downloads into the Steam version of TS2012?


Now I am not an idiot when it comes to DL/Installing of products, I just want to be 100% educated and informed when it comes to adding routes, scenery, equipment, etc. to TS2012. From my experiences with MSFS over the years and operating a VA, I always found that the add-ons for Flight Sim were always more user friendly and almost "idiot proof" when it came to installing. It seems with Steam, it may be just a little difficult to perform these additional installations.
Thanks in advance for your assistance, and please, don't laugh too hard at me and my apparent idiocy!

