My problem is Everytime I try to pop the back it’s not hard enough and I get no air. The article says to jump up so I do it physically and sometimes it seems to help. But when I watch skate videos and other skaters It doesn’t appear they are actually jumping up. They just seem to be popping the board. So should I physically jump? May sound stupid but it’s something I struggle with.

Skateboarding started in California in the 1950s.[2] The first skateboards were made from roller skates (attached to a board).[3] Skateboarding gained in popularity because of surfing; in fact, skateboarding was initially referred to as "sidewalk surfing". Initially, skateboards were handmade from wooden boxes and planks by individuals. As the sport became more popular, companies started manufacturing skateboards. Boards are also continuing to evolve as companies try to make them lighter and stronger or improve their performance.
To get higher ollies, I would suggesting resting your back foot on the very end of the tail and the front foot in the middle of the deck to allow for more slide. Popping as hard as you can and catching your board in the groove of the nose with you ankle practically resting in the groove will level the board out in the air. after this initial movement slide you feet back to the bolts on the tail and nose to ensure a clean landing.