next time think twice before you start attacking someone, or you might not get the help you want later on. Noone is perfect, and that somone understands it wrong what you write can always happen

anyway...
yes, it is possible to equip players with weapons, and no, it does not work 100% properly.
What works properly is, to equip the marine with any marine weapon, but when it comes to aliens, it doesn't, but it is possible to get it working.
okay, the general idea about equipping players with weapons is the following:
place a game_player_equip into your map and enter 1 or 2 in the field "Team master". 1 will make it work for marines, 2 will make it work for aliens. So if you want to equip aliens and marines, you will need two game_player_equip.
Now turn off smart edit, and use the "add" button to add new values.
There you enter the weapons / items the player shall be equipped with (use the value after the = ) in the field "key". And that is:
for marines:
LMG = weapon_machinegun
Pistol = weapon_pistol
HMG = weapon_heavymachinegun
GL = weapon_grenadegun
SG = weapon_shotgun
Welder = weapon_welder
Mine = weapon_mine
Medpack = item_health
Ammo = item_genericammo
JP = item_jetpack
HA = item_heavyarmor
for Alien:
bite = weapon_bitegun
parasite = weapon_parasite
leap = weapon_leap
xenocide = weapon_divinewind
umbra = weapon_umbra
spores = weapon_spore
slash = weapon_swipe
gore = weapon_claws
devour = weapon_devour
stomp = weapon_stomp
charge = weapon_charge
acid rocket = weapon_acidrocketgun
bilebomb = weapon_bilebombgun
spikes = weapon_spikegun
spitgun = weapon_spit
blink = weapon_blink
metabolize = weapon_metabolize
in the field "value" usually enter 1 there. except for ammo and mines. there you can go up to a higher amount if you want.
Now. if you would do that, you could get it working for marines, and equip them. Aliens don't get equipped.
To get aliens equipped with their alien weapons, it takes a bit more work.
go to your nsp folder and open the file ns.fgd with a texteditor. Scroll down to the last line and make a new one and enter this in there:
save & close the file and reopen Hammer.
When you check your point entity list now, you will find a new entry called "player_weaponstrip". That's what you will need to remove all weapons from the player.
What to do now is to create a trigger_multiple around the spawns of each team, or close to them.
Then you need one game_weaponstrip, one game_player_equip and one multimanager for each trigger_multiple.
Go to the trigger_multiple of the alien side and open it's properties. In the field "Target" enter "a_strip_mm". Now give the game_weaponstrip of the alien side the name "a_strip" and the alien game_player_equip the name "a_equip". Open the properties of the multimanager and give it the name "a_strip_mm" and after that take off smart edit and add the following:
Key: a_strip
Value: 0.3
and
Key: a_equip
Value: 0.5
The game_player_equip needs the weapons the aliens should be equipped with, like I wrote at the very beginning.
Now do the same with the marine side, just with another names.
What will happen now?
The player walks or spawns in the trigger_multiple, which will trigger the multimanager. Then 0.3 seconds later he will get all weapons removed and at 0.5 seconds he'll be euqipped with the weapons you want him to have. And yes, NOW it will also work with the alien weapons.
But now to the bad side of this..
you need to place the trigger_multiple 's somewhere, where the other team is not able to get. Otherwise they would get their weapons removed and would not get new weapons. And you would also need it wo place that the player can't get back to it by it's own, because that would give the marines the possibility for endless ammo/mines etc.
How you solve that, is up on you.
Another thing is, that this isn't that good for co maps, since the marines would get removed from their weapons they gained by spending a level on it.
Anyway.. Now you know how it works. If and how you use it is your problem

If you find typos, you can keep them.