How does this excel function works. =IF($E5=G$3,$D5,0)?

If the contents of E5 and G3 are the same, copy the contents of D5 into this cell, otherwise set this cell to 0. The dollar signs mean that if you copy this cell, the ';E';, ';3'; and ';D'; won't change.How does this excel function works. =IF($E5=G$3,$D5,0)?
you type this formula on xxxx cell





when the numerical value on $E5 cell is exactly equal to that of G$3 cell, on xxxx cell it will show up the content of $D5. otherwise it will show up 0