Vlookup and Concatenate

Hi All,

I have been trying to concatenate data from the same column by looking up and matching the IDs from two different sheets, but I have had any luck with the formula. Keeps giving me an error.

I have attached an excel document as an example.

What I would like to do is match the ID from Sheet1 Column A with the ID on Sheet2 Column A and Concatenate cells from Sheet2 Column B that pertain to that ID.

It sounds like a simple formula but I think I am over complicating it.

Thanks!