Understand that not all corners are 90 degrees, inside or out. If the house is drywall, then there will be a bulge at the outside corners where the steel corner bead is installed. Use an adjustable angle measuring tool (they are cheap) to determine actual corner angles and set your saw to cut angles to meet each corner as they will all be different. I would not even try the installation without an electric miter saw, even a cheap one so long as it can be adjusted to slightly more and less than 90 degrees. A few cuts with a wooden box miter is ok but certainly not for a whole house. If you are going to paint the base, it's easier to paint it first before cutting and mounting it and then give a final coat after filling the nail holes, caulking and touching up. Pre painted base is also available at the big box stores.
Remember to find and mark the studs (on the wall if you are going to paint them later or tape on the floor) as you will not know where to nail once the base is held against the wall. Also, if you are not good with a hammer, a miss will dent the base. If uncomfortable with that, drill pilot holes for the finish nails first and set them below the surface of the base with an inexpensive nail set. Then use painter's putty to fill the holes by pressing the putty into the holes with your finger and cutting it off with a putty knife while it's still under pressure. As it dries, it will expand and can easily be sanded flush with the surface.
If you're going paint grade, I'd skip the coping part so long as you measure and cut the corner angles well. Caulking all the joints before final paint makes a nice finished job also, including caulking the top of the base at the wall.
This is not rocket science. Sounds like you have played with angles on tubing projects and this is a piece of cake as compared to that. Better than Utube, there are a lot of trim instruction books at every big box store that you can refer to as questions on each step come up rather than hunting through a vidio.
You may need a few tools but buying them will be much cheaper than having the work done by a contractor. Remember the mantra of all DIY guys........every new project deserves buying new tools to get it done. Good luck.
Glen