Definition of self-quarantine

When someone came to Thailand and is required to do 14 days of self-quarantine, what exactly does it mean?

Because when I read at internet it means you should just avoid contact to other people and not do stupid stuff like partying and being in a restaurant and so on, but it would be okay to go out on a walk alone, buy necessary stuff when you keep away from others.

Just when it’s  confirmed you are infected you should go into isolation, what means you are not even allowed to do the above?

Am I right or wrong?