Your twist rate is good for bullets up to 75gr or monolithics up to 70gr (that, however, is pushing it. Some rifles can do it with that twist rate....others can't).
As for powder, Varget is a good overall choice as a start. Work up your load by starting at the minimum and working up in 10% increments until you find YOUR rifle's sweet spot for A particular powder.
Reloading .223 is a multi step process. I personally tumble, lube, resize/decap, trim (if you're using brass that was fired in your particular rifle, you won't have to worry about this so much), then resize again, primer, charge with powder, seat bullet, crimp and repeat.
If you're just going to be using a bolt gun, you could get away with just resizing the neck instead of a full length resize if it's your own brass. Some people with bolt guns skip the crimping part as well, but since I load for my AR, I do apply a crimp.
FWIW, I load my AR with 25gr of W748, as I like the lower flame temp that's supposed to extend barrel life. I've also reload with 24gr IMR 8208 XBR and love it as well. But every gun is an individual, so you'll have to find out your gun's preferences yourself.