Flagstaff Mountain above Boulder is the perfect classroom for new boulderers, with short approaches, forgiving landings, and problems for every level.
Eldorado Canyon is legendary for hard trad climbing, but a handful of moderate routes make it a realistic goal for new leaders.
Topos are the maps of the climbing world, and learning to read them will save you time, energy, and a lot of wandering.
You do not need a wall of cams to start trad climbing, but you do need a thoughtful, safe, and versatile rack.