parabolic jump

I am new to programming I tried many code and it is not working help will be great.when space bar key is released by player the player should jump in parabolic jump and the distance of the jump should be based on the how long player kept space bar button down parabolic jump should happen after player release the space bar and distance of jump should depend on how long player kept space bar down player should be able to press space bar only after player land on ground after parabolic jump I have asked this question like an essay please ignore and please help since I am new to unity all help will great to me

Heres an example of a a ball jumping over an obstacle by pressing space.[|16077]