[SampzzonE]

how can i remove the entrences? (like default ammu-nation entrence) (that yellow arrow)

[Konstantinos]

You cannot remove a specific yellow thing (default), but there's a function to remove all of them at once.
It's called DisableInteriorEnterExits.

[Vince]

A simple search for 'yellow arrow' (they're called enex, by the way) yielded this, this and this. And there's probably tons more. It's really not that hard! Put some effort in it.