Adding another IF statement

Hi there,

If I am duplicating a post, I am sorry, there are so many on here and I do not know what words to search with

I am simply using a VLookup, but am stuck

=IF('datasheet'!$L2=1,VLOOKUP($A5,'datasheet'!$A$2:$T$500,14,0),0)

The reason for the IF, is that there are two data sets I want to refer to based on L2.

Where I need help is that I need to edit the above formula so that the output also looks at the month of each row which is 'datasheet'!D2:D500

Hope this make sense???