power store does not have a way of reordering the products on the results page, you would need to do this manually by adding a sort column to the products table and numbering this column in the order you would like the products displayed, the n edit the products recordset on the results page to add an Order By clause to order the records using the new sort column.
This should not be too difficult to accomplish if you are familiar with editing databases and SQL code, but it is not a modification we can offer support for.