How to keep my character from falling through the floor?

i have put colliders on the terrain and the sphere (my character im a beginner) and he still falls through and its at 0,0,0,? please help!!!

I’ve seen this when I add a character (like the soldier from the Locomotion demo) who is 100 times too big. So you set scale to .01 to make it look right. But now the character controller is 100 times too small. So set its height to like 200 and radius to 50