First, download this template vmf:
http://www.mediafire.com/?2pbdpi4dlugc6ab (the materials are only necessary if you want to use the health pickups)
If you're making a map that allows player respawning, you need the game_weapon_managers for glocks, hkp2000s, and knives (green box on the top pic). They prevent players from spamming those weapons by killing themselves over and over again by putting a limit of 3 of each dropped weapon.
Infinite weapon spawns
If you want infinitely respawning weapons in your map, you can search for your weapon in Map -> Entity Report... and check By key/value, then put the weapon's name in the second field and leave the first field blank. Select the game_player_equip with (your weapon)_equip1 as its name.
If you search negev, m4a1, or ak47 you will find game_player_equips with _once1, _ct1, or _t1 in their names. Ignore those for now.
Once you find the game_player_equip for your weapon, click on the trigger surrounding it and it should select all the entities in a group. Also select the game_weapon_manager in front of the group. This is necessary to prevent players from spamming weapons and lagging the server.
Now copy your current selection, open the vmf to your map, and paste it where ever you want. If you want to make a duplicate of the weapon you just placed in your map, unselect the game_weapon_manager since you only need one in the map and use paste special (ctrl+shift+v). The editor will make a duplicate with unique names.
One time pickup weapons
Since there is only a single one time pickup weapon included in the templates vmf, you will need to modify it to use your desired weapon. Select everything in the blue box (in the top pic) and copy paste it into your map. Replace anything that says negev on each entity with the name of the weapon that you want, including the outputs on the trigger_once. Also, change the model for the prop_dynamic_override.
(yellow box on the top pic) Same as with the one time pickup weapons, just rename anything that says m4a1 or ak47 with your weapon, change the trigger's outputs, and change the prop's model. You only need one of each of the filters in your map.
Health Pickups (bonus/optional)
(purple box on the top pic) You will only need one copy of the point_clientcommand in your map. Copy which ever health pickup you want and put it in your map (Blue = 20 HP, Green = 50 HP, Red = 100 HP, 10 sec respawn time). You can make duplicates by using paste special.