As dropt mentioned, those values are given to you by whatever pool on which you choose to mine. For example, on p2pool you use a BTC address as your user name and anything as a password. If you were to mine on my p2pool node and your BTC address is 1DevLdogN52pHdjZnsgi4HzreFDB4ZHVre you'd enter:
cgminer.exe --bmsc-options 115200:0.65 -o http://104.131.12.128:9332 -u 1DevLdogN52pHdjZnsgi4HzreFDB4ZHVre -p x --bmsc-voltage 0800 --bmsc-freq 1306
PS - unless you want to mine to my address, I certainly suggest you use your own BTC address