Sum If Forumla to some values assocated wtih months of the year

Hi-

Please see attached spreadsheet. I am trying fill in the "Buy", and "Sell" columns in my Turnover tab. It pulls data from the Eze data tab. I want to add to the sumif formula to only add the Month in column A in the Turnover tab with the assocaiated Month data in column B in ezea data. I think the issue is the format the i download the data in. Please help me out.

Thanks