So I’ll be straight with you… it’s not that easy to make it 
- Blips (on-map indicators): Round circles on map (AddBlipForRadius)
- Blips’ documentation: Blips
- Markers (ground 3D indicators): [Request] Draw a marker
- Markers’ documentation: Markers
- Area checking: Checking if someone is an area
About the guns:
- GiveWeaponToPed documentation
- RemoveWeaponFromPed documentation
Long story short, you have to separately create: blips (on-map, can be done once because they’ll stay on the map), markers (3D, you’ll have to run it in a loop, otherwise they will not show up), and you’ll have to create a functionality that is checking if the player is inside of the circle (marker). If so, give him a gun, otherwise take it back.