Jumping issue

I appear to be having trouble descending from a jump. I can jump but instead of coming down I stop and hover in the air. If I strike the space bar again I only go higher. I never automatically drop back to the floor. Could some one point me where to look and what do modify to make “what goes up, must come down.”

Thank you

I’m new to this and I’m fairly certain I missed something either setting up the JUMP or configuring its parameters. Can anyone provide me with a how-to to fix this or link me to something that can?