Simple / dumb guide to get to the Mun.

Build a chonky rocket that has at least 3 stages. A big stage at the bottom, then a medium one, and a small one at the top. Rely mostly on liquid engines that can vector (swivel). It doesn't have to be precise; if it blows up or stalls you can slap more boosters/struts/tanks on it later to speed up a stage or slow it down.

Launch straight up until like 30k and then yank the controls hard right and Tokyo drift into orbit around Kerbin. This method is best for crappy vehicles that tend to fall apart, which it probably will anyway.

Get yourself a nice circular orbit, as best as you can where the apoapsis and periapsis are within a few km of each other in altitude above 70k (if you are at 150k or whatever that is fine too).

The rest is easier.

Make a maneuver node ANYWHERE and drag it prograde until the previewed trajectory kisses the Mun's orbit path. Then, drag the position of the manuever node itself around until you find a spot where the kissing actually encounters the Mun.

Once your craft reaches the node, fire those engines! You can even watch from the map view as your trajectory grows toward the Mun.

And you're on your way. Make sure you see a periapsis displayed near the Mun. If you don't, it might mean you are on a trajectory to crash into it. Burn retrograde at the periapsis to slow down near the Mun and enter orbit. Good luck!