so, i decide to make a trigger where it involves a player unit getting on a beacon. the trigger kills the unit and creates another unit. if i check for players "players 1-3" for this, will it create one unit for each player?

Use Current Player if you want to create the unit only for the player that brings the unit to the beacon:

Players 1-3
Conditions:
Current Player brings at least 1 unit to 'beacon loc'
Actions:
Kill 1 unit of Current Player at 'beacon loc'
Create 1 other unit for Current Player at 'beacon loc'

Use the Force if you want to create the unit for every player:

Players 1-3
Conditions:
Current Player brings at least 1 unit to 'beacon loc'
Actions:
Kill 1 unit of Current Player at 'beacon loc'
Create 1 other unit for Force 1 at 'beacon loc'

hmkay, tnx