aspire one 150 xp, how to use BIOS passwords

i am given aspire 150 xp, but with no manual nor on cd. he said did not come with manual, not even cd. he got cd special for me but no manual on cd either. this BIOS has three passwords, what are SUPERVISOR and USER and HDD (what is hard disk drive). there is only quick guide which mentions this but for linpus not for xp and does not mention all passwords, only SUPERVISOR and USER passwords and like USER password is for linpus not for BIOS.

can someone tell please where is description of function of each three BIOS passwords of aspire 150, like url address will do. not windows passwords because i know how windows passwords are but i do not know how this BIOS passwords are. i have looked acer web site faq but i don't see answer there. specially i like to know how BIOS passwords work together all with each other so i dont lock myself like many people here. plenty questions here about how to remove passwords but not question how to use passwords. thank you for read this. could be in BIOS forum but also beginner so i hope put right. hoping for answer too.