Package import on Proteus

Can any expert help me with this?
So the thing is I have downloaded many libraries from SnapEDA but the main issue is that mostly the packages do not work. However, all the connections in my Proteus are fine the package gives an error as "No model specified for U2. [U2]
".
I recently downloaded the ATTINY84 package, but there was no location field in the package, so how do I upload the program to it?
I've downloaded Arduino Libraries from another site and their library works properly but mostly the parts I import from here don't work.
Someone, please assist me