If you are creating fy (fight yard) or aim map, you will need to spawn weapons on the ground for players to pick up.
It is very simple to do in your own map.
Switch to Entity Tool (Shift+E):
Under Objects, use drop down menu and select any of the "weapon_" entities with a name of the weapon you want to use:
Example: weapon_ak47 entity will insert AK-47 gun on the ground.
Left-click on the ground in perspective viewport to place selected weapon entity:
You can place weapon entity as-is without rotating or aligning to the ground, but you may see the weapon move and fall on the ground at spawn due to physics.
You might want to rotate and align the weapon entity to the ground:
Full weapon entities list you can use:
Do not include buy zones if you do not want the player to purchase any weapons at the start.
Compile and test your map. You should now have weapons spawned on the ground for players to pick up.