Can you me on this since im struggling on this since day 1

Of Ok here is what I am thinking.

Simple replacement means when one element or compound moves out of another element and is replaced by this compound.

For example if you have A+BC  AC + B

Most of the time the one which is replaced is found on the right and the left one is going be only one element or compound.

Double replacement means when the two compounds exchange the positive and negative ions. Ok let see this example:

AB+ CD AD+ BC
this means if A have  + sign and D has - sign they will share to form new compound the same is true for DC. Don't forget that all compounds are formed from positive and negative ions. 

                                 QUESTIONS
CUSO4 + NA2S CUS + Naso4[ double replacement]
KBR +Pb[CLO3]2K[clo3]2 +PbBr [ double replacement]
I do not  think these questions can be single replacement.
I hope this may helps you.