Manual:Singleplayer/Hire & Fire
Using this screen you can add further personnel to your organisation. While especially in the beginning people do not trust in your ability to counter the aliens they might be more enthusiastic (and therefore willing to work for you) as you proceed in the game. On the left side you find all members of one group listed.
Hire & Fire
Place a check in the box next to the employee to hire them, likewise clearing the check fires them, if you right a fired employee, it will remove them from the employee list. You can discard / select them as often as you want, and they will never get angry at you. But please be aware that personnel you hire in one base won't be accessible from another base. So if you want to fire someone make sure you are in the corresponding base. Also you should keep in mind that the amount of personnel that can work in your base is limited by the number of living quarters and working facilities.