This would be a typical first cloth layer. This is continuous strand surface veil or mat. It will stop the heavier weaves yet to come from showing through your surface coat over time. No need to apply it to the flanges: just the part.
You may be tempted to use a chopped strand mat, but the binder in it will react negatively with epoxy resins.
I will now wet this out with laminating resin.
Aeropoxy 2032 with a 30 minute hardener.