Hi, after playing the Sims 4 for a while, I've decided to try Sims 3 again. I installed some custom content for the game like tops, pants etc. Like many others, I have installed the Mods folder from the tutorial that was on this website so I could use the .package files that I'd downloaded. I did everything that the instructions told me to and had the no intro mod in my folder but it didn't work. I thought that I'd done something wrong, so I tried this again, deleting my Mods folder and downloading it again. It didn't work. I tried it multiple times after, making sure that I read through the instructions thoroughly but I still haven't had a positive outcome. I've looked through different forum posts where other people have had a similar problem and tried everything on there (for example, creating a mods folder and downloading the resource file separately) but nothing is working! There is a certain skin that I really want but I know that you can't get them in sims3pack form. Does anyone know what I can do to get it working?
Thank you!

If the first 2 *.package files doesn't work for test purposes (and keeping them after the test), then adding other Custom Content in *.package format in your Mods\ setup won't work either. Those initial two files are crucial to see if your Mods - Framework works or not.

First thing to ask, on what Operating System are you on (Windows / Mac / Other)? On OS Windows the tutorial on the Sims.Wiki are sound and should work, though Win 7 had a glitch where it couldn't read the Library\ folder, but now a days there are workarounds to it.

On OS Mac can be somewhat a little bit tricky as you have to make sure your Sims 3 userdirectory reads Documents\Electronics Arts\The Sims 3. I am not on one, but read, there could be a shadow directory somewhere on your system and that's not the one to use. But unsure where and would leave this to someone with more experience with Mac OS's

No experience with other type of OS.

Regardless of PC or Mac, please make sure that the TS3 game folder into which you are adding Mods, Packages, Resource.cfg is actually the live folder. The phantom game folder thing can occur on any operating system; some Win 10 users are having trouble with the game putting a TS3 folder into OneDrive, where it doesn't belong.

The way to tell if a game folder is live is to check the modification date/time of a file in there called DeviceConfig.log. If not in Detail View, right-click on that file and select Properties (or Get Info if on a Mac). The modification time should match your latest attempt to startup the game precisely. If you aren't sure, launch the game and the modification time should update immediately. If it doesn't match, you have another game folder that is live somewhere on your system and you are adding package files to a folder that is being ignored.

Also, checking just in case, but have you tried deleting your game folder's 5 cache files with the two sample test mods (only) or NoIntro only in place? They will regenerate upon launching the game, again if that is your live game folder.
CasPartCache.package
compositorCache.package
scriptCache.package
simCompositorCache.package
socialCache.package