@BeeboBrink The above covers things in general, but I want to mention a couple of details in case they happen to matter to you. First, I'd suggest zipping the folders before transfer (right-click and Send to > Compressed file) to keep them from getting corrupted. Saves should be fine anyway, but mods sometimes are not. You may also want to transfer the Tray folder, which holds your saved households and builds.
Second, please make sure you're installing Sims 4 somewhere that is NOT in Documents. The default C:\Program Files\EA Games is fine, as is a custom folder. But you don't want the program files and user files mixing—that can only lead to problems.
