the data in my portfolio tab (or any other tab) in TWS classic. Do I have to use the API or there a simple download link I haven't found? Thanks in advance.
I think you download the separate api from IB and open the example spreadsheet file in that and modify.
If you right-click on a watchlist you can import/export the financial instruments or you can export the page contents (all the columns). Both are in a CSV format that can be opened by Excel.