Welcome to the forum.
There's plenty of helpful folks here, and a few GT builds, so I'm sure you'll get plenty of help.
I would just say to be careful not to tweak that aluminum frame as you build. Also, if you're using a kit engine, flush the fuel tank well, remove and discard the filter, petcock and line, and replace them. There is also usually no need for a chain tensioner, so toss that as well. If it should loosen and rotate into your spokes, it could spoil your day.
Here's an example of an aluminum frame build with these mods;
Good luck, and post all the pictures you can of your build process, we love to see it happen.
Here's a GT build I just saw today;