Hey mort,
I reckon for people that are not used to balance sports (like skateboarding, skiing, surfing etc) the ability to easily take the weight onto one leg does not come naturally, especially when you add in the complexity of all the other things to think of when trying to get into the straps.
If this is not you... forgive me! But others may find it useful.
I like to think of this guy
To balance on the one leg you have to bend your knee, drop your hip and place your weight over your knee.
In this photo, Daniel-san is getting ready to put his front foot into the front strap. Sure the boom is a bit high but I think that's 'cause Miyagi was a short arse and taught him some bad habits. You should be able to take your weight through the harness and your rear leg and be able to do the hokey pokey with your front leg. If you can't do this, you will struggle with the rest.
This one is perhaps closer to reality although he's an advanced windsurfer on flat water who doesn't need to bend his knee as much as you should.
The well known windsurfer, Yamaguchi, was renowned for his cat stance technique of getting the front foot into the straps.
Downforce and stability are the key. Downforce is gained by weighting the harness line, Yamaguchi and Daniel-san are the secret to stability. Once you have these sorted, the front strap is easy.
Now the back strap is a different story....