How do I get in Ammu Nation [GTA V Online]?

I'm playing GTA V Online right now. Just my weapon has gone empty and I wanted to buy my new monition (standard start pistol) and have first ever searched an ammu nation shop (is not there a way to let the on the map to show?) And found. I can't enter it now.

How so?

I play on PS4

As far as I remember individual items are gradually released

Think you have to work as a new player only some story missions or missions in general to unlock this. This regards the game as a kind of "tutorial". Do not ask why.

I also believe during missions is the disabled