I went to college in upstate NY. One night my friends and I went to Lake Ontario (which I first thought was the ocean because I'd never seen a lake large enough to have waves; I was never good at geography lol). Anyway, the Northern Lights were active, and I thought I was having a flashback! 😁
I missed the lights, however, I can see them from my home. We get the Aurora Australis down here, and this weekend the lights were seen as far north as Auckland in the North Island.
https://www.nzherald.co.nz/nz/aurora-australis-lights-dazzle-nz-skies-south-island-residents-first-to-see-the-show/SFHJM4RXEFGIFCER4ME4PR4LQ4/
Here is an example, which will better explain what I was getting at. You don't need to feel silly, as we were all beginners at sometime or other. There are several ways to achieve this, firstly, you should still have the vector letter, by using 'from vector object', in the selction tool bar, invert, delete. Probably, the best option for you is to use the eraser tool. I added a shadow, to demonstrate that the pattern used in the letter, shouldn't be in the empty spaces of the letter B (counters as they are called).