Importing Assets always gives errors

Hi There,
new to Unity here!

99% time I import a custom asset downloaded from github or different sources from the assets store,
I have compile errors.

Until now I’ve find a very “empirical” solution that is to remove the ProjectSettings folder contained in the .zip I’ve downloaded and only import the “assets” folder removing also the Editor folder if present

Is this correct or am I missing some important method to import custom assets?

Thanks

What are the errors?