where do i put new add-ons

cars
maps
objects

thanks as u can tell from my name im new.ty once again

maps go in garrysmod/garrysmod/maps

objects if not in addon format go in garrysmod/garrysmod but only the LUA, materials, models etc. not the whole file if you get what i mean.

cars usually go in the same unless in addon format which means they go in garrysmod/garrysmod/addons

See if there is an “info.txt” file there. If there is one, place the folder containing it to C:\program files\steam\steamapps\ your steam name \garrysmod\garrysmod\addons.
If there is no info.txt, see if there is a readme or any other text file there. It should tell you instructions.
If there is no readme, go to the download site and search for instructions.
If you see no instructions, contact the author.
If you cannot contact the author, you need to install it manually.