I l finally earnt to bunny hop properly on a BMX having tried & failed for ages on a MTB. Once you get it, it's like riding a bike lol, you never forget.
Before then I used a cheats (think it's sometimes called an English) bunny hop, where both wheels leave the floor at the same time, rather than manualling then picking up the back end. Maybe try to get the hang of this first, it's a bit easier
Hard to explain in words how to do it... I sort of pump my bodyweight hard down through the pedals, sinking my hips (saddle needs to be low) then jump up, pointing my toes down a little, which seems to lift the back end. Don't pull on the bars with your arms, you'll get an initial lift but that'll crash back down without much control.
Although not a "proper" bunny hop, you can still get good air off a small lip in the trail, and use it to clear non rollable drops. I use it much more than the proper (American?) hop as I'm much more confident in my ability to do it well under pressure.
After a few years practice I can just about hop my MTB "properly" in the car park, but don't have the skill to do it while hurling down a rocky slope.