How do I import?

I've downloaded the .zip files I am interested in, they have the unity package files and stuff, but the VRchat creator and unity both say they aren't valid files. Am I doing something wrong?

• On VCC, clic New, give project a name etc
• Clic open project and wait until unity fully opens.
• To import a .unitypackage, just double clic when unity is open, return to unity and clic Import.
• Remember, all avatars uses shaders, Mame uses Liltoon i think, import it first.
• Import avatar, clothes, pps, scripts, etc.

Thank you so much! ^^