cda itself is not a file format, it is simply a reference to audio cd tracks - the cda files themselves do not contain any audio, that is hidden away on the cd.
Use Express Rip (www.nch.com.au/rip) to rip the audio off the cd.
Use WavePad (www.nch.com.au/wavepad) to edit the ripped files.
Use Express Burn (www.nch.com.au/burn) to burn the files in "Audio CD" mode onto a blank disc.
