Each line in the truth table is one term. You AND the true or complement values of each input to compute the term. Once you have all the terms represneting the ones in the output you OR them all together.
you know itz quite simple see take a sentence for instance:
1.I WILL WORK IF REDROSE AND PAPABRAVO GO OUT.
2.i WILL WORK IF REDROSE OR PAPABRAVO GO OUT.
SO,
as far as 1 is considered u will work when both go out and while for 2 u will work even if one goes out.
Same is the cause with boolean
Just u need 2 work out abit