Importing Packages

alright so i downloaded a package which has some guns that im trying to use for my game the package is called fps kit & when i downloaded it its a zip file that can be opened in unity ; so i went to unity and tried to import it as a package but i dont see it , i can only see it when im searching in library.( & the only other way i can open is by searching in library and clicking it which would bring up an entire new project which im not trying to do only trying to import it into my current project) Any ideas as to how or why?

Simply unzipp it then trag and drop it into your project tab and it will import.

its a zip file but to the left of it it doesnt have the zip sign it has the unity sign, do i change its properties to open with folder to unzip it because right now it will open with unity