How do you get downloaded custom sims to work on sims 2?

I downloaded a bunch of custom sims (eg. Angelina Jolie sim) into my Sims 2 Downloads folder as Zip and extracted them, however they still don't work. I don't have any problems with custom clothing or furniture, but whenever I try to download a custom sim it never works.How do you get downloaded custom sims to work on sims 2?
My first stop would be wikipedia or google for a quick reference. I actually had a similar question not even 5 days ago, but I couldn't find the answer. If it's possible, try getting help from someone with more knowledge/experience/expertise, like a professional if it's possible. This can be pretty important.



I saw a forum with this online, but I didn't have time to read it all. Try checking it out. I want to help out more, but I'm not 100% sure about the answer. Sorry I'm not much help. I hope you found your answer! Good luck!