I would like to learn how I can apply this to guitar so I can start writing my own music and be able to put what is in my head onto the guitar and have it be close...
I can only speak for myself here. I know a lot of theory but I never use it when writing a song. I might go back after the song is done and analyze it out of curiousity but theory doesn't affect my decisions. Only my ear and heart. My point is that you don't have to know theory to write music. Just do it and learn theory parallel to that.
Learning the major scale and what you can do with it is also a good start.
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