Good morning,
I am having problems connecting to the db on pl/sql developer. If I click the db link the pl/sql developer app opens but it doesn't show connected to any db. How can i solve the problem, thank you

What happens if you go to Session > Log On and try to connect? Are there any error messages?

place the system in a directory whose name does not have a space, for example:
C:\Program Files
Place
C:\ProgramFiles