How to make a CD of an acoustic piano (the hard way)
Firstly, you should read 'How to make a CD of an acoustic piano (the easy way)' and don't come back.
Still here? Oh dear...
OK, it looks like you want to handle the technical side of the recording yourself. Yes, it can be done, but you don't see top concert pianists doing it themselves, so that has to be a kind of warning.
But if you are determined, firstly you will need to follow the advice on pianos and auditoria in the 'easy' article. You might be content with a lower standard for all sorts of good reasons, in which case you can do it at home. But the result won't be commercial CD quality.
You need two microphones. These should be capacitor microphones. I always recommend the AKG C414 because they can record anything and work well in stereo. At a lower cost, the AKG C3000B performs well too. Choice of microphone (of professional quality) is not so important as pianist, piano and mic placement.
If you have an upright piano, don't expect good sound quality whatever you do. But do your best.You can open the lid and record the sound coming out from there, or you can pull the piano away from the wall and record the sound from the soundboard. If you are doing this at home, then you will have to have the mics quite close otherwise you will pick up far too much reverberation from the room. I suggest spacing the mics about half a meter apart a distance of about half a meter from the piano as a starting point for experiments. There are other mic techniques you could use if you have the inclination to research.
If you have a grand piano at home, place the mics at the far end of the instrument, facing you, once again using half meter spacing and half meter distance. This will capture a sonorous and weighty sound that is suitable for classical piano. If it is over-sonorous, move the mics around the curve of the instrument closer to you but maintaining the same angle towards the strings they had previously. Once again there are other mic techniques, but this one is a good place to start. If you are recording a grand piano in an auditorium, then the mics can be further away. Experiment.
Now there is the question of what do you connect the mics to? I would suggest a computer-based system because it is easier to make finely-detailed edits than it is with standalone workstations.
In an ideal world you would buy a Digidesign Mbox audio interface, to which the microphones are connected. This comes with Pro Tools LE software, which is perfect for the job. Also in this ideal world you would buy a computer that is listed in Digidesign's compatibility information, and do not install any other software than what you absolutely need to make the recording and CD's. Ignore these two pieces of advice and you will struggle.
The next part of the process - the recording and editing - is the part that is going to take you months of experience to get the hang of. That is why this is called the 'hard way'. But it is possible, if you have the determination to do it.
Once you have a complete, edited recording on your computer, you need to transfer it to CD. For preference you would use a pro-standard software such as Sony CD Architect (PC) or Roxio Toast with Jam (Mac). Actually, you should just do that because if you use software that is sold for general-purpose CD burning, rather than for professional work, you will only get into trouble.
At the end of this long process, you should have the ability to produce CD's of an acoustic piano. But really, there is an easier way...