As salaamu aalykum,
How do you distinguish the daaef hadeeth, I think it's already been answered, but you'll have to go back to the chain of the narraters like when you have in a hadeeth.. hadathanaa yahya , qaala hadathanaa , ibnu sura3ah ...etc
you look in kutub ar-rijaal .. like kitaab "Tadreeb Ar-Raawiy".. that is basically a dictionary of all the muhadditheen.. it states who is . Thiqqah(Reliable), Saduuq(Trustworthy), Khatthaab (Liar), Daeef..and etc
If the hadeeth is Daeef then Yeah you disregard them. although some hadeeth.. are daaef but then they're taken to rank of al-hasan, cause they might have something called shawaahid wal-mutaaba3aat!!
InshaAllah This will all become clear to you once you've studied it, some Ulamaah say it is very very important for the student of knowledge to study this... and I'd have to agree with them!!
If you have any more questions concerning this topic then please feel free to ask.
Allah Ma3ak

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