Sims2 custom content loading help please.?

i will be as detailed as i can be. i have been trying to get some custom cont. on my sims2 game. but it hasnt worked. i tried to follow the directions i was given but im still not getting it. i go to my desktop and click on the filed i downloaded. then click extract to (using jzip). i made a new folder in the sims2 folder and named it sims2 downloads. extracted all the files in there. thats supposed to be it right? i checked to make sure i have the expansion pack for it and the meshes and such. why isnt it working? please help!!!!! if im not being detailed enough let me know.thanx a mill..........