The handle is really only needed for getting in, if you have the trapeze loops set so low you have to lift your bum onto the deck.

Getting out, it's useful to have toe-straps so you can get out far enough to put some weight on the trapeze harness while still feeling secure with your feet under the straps. Then you bring your front foot out to the gunwale and push.

Like Karl said, practise on land is a great idea to get started.