How to use Scid chess?

@bufferunderrun im using 4.7.0/8.6.8 version.
I just try with the "example" database...
It happend when i go to play/training/opening trainings... there a bar like "im looking the games" start to run, and after a seconds says that.

I dont know much about this (as you can see). Im looking for a good database but dont know exactly from where download, or what to try.

@bufferunderrun I try with another database... one from magnus carlsen games... and is working!!!
I dont know anyway how use it :-)
I made some moves and after a while the program tell me "this move is not in the database"... but never tell me nothing about aperture. This is used like this?

Thanks!

I guess you use it with your own repertoire database. Basically, you create a database, let's say for White, where you have all the theory. Good moves for White and all the replies, good and bad, for Black and use it to memorize the repertoire.