Sites like TruckyMods or the Steam Workshop are generally safer than generic file-sharing sites which may host "leaked" or "washed" files containing viruses. Installation and Setup If you are using a zip file for a mod or a manual patch: How To Upload & Unzip Mods To American Truck Simulator
You have an older computer, rely on legacy mods, or want a frozen, stable version for a long-term career. Download File American Truck Simulator V1.31.1s.zip
V1.31.1s cannot read save files from newer game versions (V1.32+). Start a new profile specifically for this build, or use a save file converter (rare and risky). Do not copy your main profile into this version. Sites like TruckyMods or the Steam Workshop are