Visible Columns vs Available Columns

Hello,

I am having trouble with my visible and available columns, after i click the filter icon in my database. Yesterday I moved all of my items from the 'available column' to the 'visible colum.' Today, I downloaded my data to an excel and many of my items were missing. I went back to my database and noticed that all of the items were again in the 'available colum.' I would prefer not to move them over everytime i do a data download, because i am downloading frequently. How do i ensure that this does not happen again? 

Thanks!