Noob question: practice range enter combat button greyed out? How do i enter practice range

I've done it before when i first bought the game, came back and now whenever i hit practice range the join or create a unit is yellow and i will select rifleman with a 1/6 beside it and the enter combat is greyed out. Ive tried to do it with other classes too. And clearly it doesnt want me to make a whole 6 characters as wjen i hit escape it is just leave server or quit game not previous page before the class listing. What am i doing wrong