Order by - if you want to order selected data - write a column name here. If not - leave this field empty
Direction - use this only with Order by statement. If it is emoty - then choose - NO
Limit - if you want to limit your query result - use this. If not - leave this field empty.
Store selected - your stored data count must be equal to selected data count, so if you select 2 columns, than you need to store 2 columns somewhere. If you want to store to String Variable = paste Store to String data and leave Store to Number (none). If you want to store to number variable - use this field and leave Store to String (none).