Basically, just go mental on your first yin, take far too much stuff.
On your second trip, take half as much.
On you 3rd trip, throw away some more.
Then start upgrading if you continue doing it.
Just take what you’ve already got/think you need.
Buy some thick bungee straps, to fire stuff on the bike(thick poly bags will do for water proofing), bungee will attach anything to anything really, but most like handle bars, top tube and seat railings..
Then while you are out, put all the stuff you didn’t in the one bag/couple of bags, and never take it out again. repeat.
It’s a learning process. Juts batter in is basically my advice, do some 1 nighters to begin with.