It's just like running 120 with an extra conductor. You use the 3+GND cable. You'll run it all the way from the breaker box. Put a new double breaker (pops both on a short on either side) in, and wire the ground and white in like with 120V, red to one hot, and black to the other. You'll need to find out what plug the human toaster is so you can put the right socket on your outlet.
I've run 240 to the garage for my welders, and to the hot tub, and now my box is full, so I'll have to do it again for a branch box in the garage.
Depends on a few factors.
1- Do you have 2 spaces available in your load center?
2- Is there an easy path (chase) from the load center to where you want the power?
3- Would you be willing to look at conduit on the outside of the house?
4- What distance (how many feet run from box to device)? This CAN make a difference in wire gauge required.
5- Possibly most important, how many, and what type of firearms are you willing to part with?
Question marks added.Getting to a second floor room might be a routing issue for a green horn. No knock but if you have to ask you are green horn.
Is your existing panel loaded? Will you over load it with this addition? Will you need to side car the main panel?
Hire it out.