There are many tutorials available online regarding this process, and HE Gilliana's is one of the best. You can take a look here if you're interested in learning more.
I'm a bit of a novice with this whole process, and I came to discover that 1) the gutta bottle I was using was leaky, dispensing way too much, and periodically dropping blobs everywhere and 2) some of the dye got mis-labeled resulting in some "interesting" colors. That said, having spent $20 from my very tight budget on supplies, I wasn't about to throw in the towel. Here's my first banner (with my husband's behind).
To the right you can see my bear and garlic flowers in a slightly different configuration. My banner (and device, for that matter), are pretty simple compared to many people's, but I'd rather have simple and recognizable than a complex mess for my first attempt.
The banner is a swallowtail shape, so I used the empty triangle on the right to make a little pennant which totally breaks the heraldry rules, as it is basically a "resume," with a ball of yarn, knitting needles, and a spindle.