Yes, CRO is oscilloscope.
If you got one, then you should hook up a signal generator to the input of your amp. (or if you have a test CD with tone signals). Hook up your CRO to the output of the amp. Slowly turn up the signal, you should start to see the waveform on the CRO grow larger and larger but keeping a good sine waveform.. At some point, you should start to see the top of the sine waveform flatten out, the amp is clipping. At such stage, turn your bias adjustment VR until you see that the flatten portion of your sine wave is symmetrical on the top and bottom. You are done.