VEVOR Baseball Batting Cage, Softball and Baseball Batting Cage Net and Frame, Practice Portable Cage Net with Carry Bag, Heavy Duty Enclosed Pitching Cage, for Backyard Batting Hitting Training1005CM

I have questions about the baseball batting cage. We want to use it indoors, but I cannot see any base frames between the arched frames. I cannot figure out how to make it stand without a spike on the floor.