I use head rubs for positive reinforcement. All of mine enjoy just having their cheeks and the base of their ears rubbed so when they do something good I tell them and pet them. I find that treats just haven't worked for me in the past.
Usually I don't really have to make them move, I just have to try and direct them. They kinda hop on their own. So if you can just get your bun hopping forward with a low jump in front of them, just do this a few times and I swear, there is a moment when it "clicks". It's happened over and over, they all of a sudden just understand and do it. It's weird but every rabbit I work with has an epiphany after roughly half-hour/45 minutes.
We built the jumps ourselves, there are instructions on how to do that on our site as well. Whatever you use, just make sure it is capable of falling, especially as heights get higher. Using fixed jumps can lead to an injured bunny.
In order to get them confident, I find just a lot of repition is the key. Do it over and over (Although try to keep the sessions short, around half hour, and always end on a good note) and just keep with it.
You can start them on low jumps at any age, although I've noticed around 10-12 weeks is probably the youngest to try. We do not do any jumps higher then a few inches before they are 9 months as we want to prevent joint injuries.
I think any rabbit can learn and I don't think it's you
It's your first attempt, it will take a bit longer.
No worries on the questions, ask as many as you like!