Hey mate
Not exactly sure what you mean by "hop up onto a bench"
But i'm assuming since your starting out that the following will be most helpful.
I'd say the best place to start, is with a bench about a foot high, or something similar.
Roll up to it, with your bad foot forward. Cranking with your bad foot, get your front wheel onto the bench. You should now have your good foot forward. Keep rolling forward the hole time. However just after your front wheel is on the bench (and your rear one is coming closer), throw all your weight up and forward, and pull the bike up under you.
Hope this makes sense, i'm not great at explainging this kinda stuff on paper. I'm pretty new to trials myself, so some of the other guys on here may be of much more help
Note: just in case you're not clear, your "good foot" is the one you naturally have forward. e.g. if you do a jump, or even if you just standing up rolling down a hill, which ever foot you naturally put forward is your good one.
Cheers
and enjoy