That kit will get you the soldering iron, several tips, some solder, an iron holder, a soldapullt and a pair of flush cutters - pretty much a complete soldering toolkit in one go.
I would recommend that if you don't have any of the equipment already.
Then all you would need is something to practice on, like a PCB from an old electronic appliance.
After a bit of practice, you can start buying the bits to build your own keyboard, such as PCB, switches, diodes and so on.