Installing wood floors is a lot more complicated than painting your walls or replacing the hardware on your kitchen cabinets. Wood flooring requires special tools that you will likely have to rent. You will need to make sure the room you are working in is flat, that the subfloor material will work for wood flooring and that no moisture issues are present that will damage the wood long term.
You also will need to know how to center the room, how much space should be left for expansion gaps and how to work around obstructions like closets, fireplaces, bay windows, staircases and cabinets. If you make cutting mistakes, you may end up running short on your material and not have enough to finish the job.
For all these reasons, installing wood floors is not recommended as a do-it-yourself project. In the long run, you will save money and time by using a professional installer.