That’s a pretty ambitious project for your first month of 3d work. The basic problem I see is that you’re still thinking 2d: outlines, rather than volumes. However, Gollum999 just published a tutorial on Making a carving which you might find useful, since he starts the work from outlines, then puffs it up into a 3d carving, like a wood carving. I haven’t done the tutorial, so I can’t vouch for how easy it would be for a beginner, and Gollum999 does recommend starting with something simple, to get the hang of it, before jumping into a major project. (I’d consider your coat of arms a major project.)
Anyway, check out the tutorial, good luck, and if you run into snags, post again.