@Regular trumpet player I spent a total of 4yrs in DCI, and I marched in two Top-12 corps (Velvet Knights – ’86, ’88, ‘89 & Blue Devils 1990), and I was an instructor for 3 seasons for a start-up corps in mid-90s. I haven't been around the activity since then, but I'll try to help, especially with things that may not be obvious. Fortunately, I keep some tips and info saved in a document for when I see someone ask a question like yours. I can paste that into an email if you are interested. When I marched, we did not have social media, the WWW, smartphones, or any of the other tech toys you do now. Still, some things never change. It would help if I knew more specifically what you are interested in knowing. Also, I’d like to know what level of corps you are trying out for. E-mail me at eric2022@outlook.com, which is a temp email address. I’ll keep it open for a couple of weeks unless I start getting a bunch of junk sent to it.