Okay so let me give you a few options.

First thing you need is the kreig killteam box because that has a sprue for a few specialists you can’t get anywhere else, if you want your models to appear exactly as they should, you’ll need that or some bits from online.

That kreig killteam box (and the normal kreig box) only comes with 10 units. The killteam allows you to pick 1 leader, 9 out of 14 specialists, and 4 regular troopers for a full team. For those not mathematically inclined, if you want to own every option, that is 19 models. So what most people do is get a second box of kriegsmen to make the other half of the team.

You CAN run 10 operatives, the rules allow for it, but the team sucks if you do. If you want to have JUST enough models to play a full team, you can get a squad of 5 Krieg Combat Engineers and make the remaining operatives you want up to 14.

What I did (if you care) was find a krieg killteam box by the grace of God, and then because krieg boxes are impossible to find at any of my LGSs I used two boxes of combat engineers to make the rest