With your equation editor open, select the "Ordered View" icon at the upper left. You will also need to have the "Automatic Solve Order" unchecked at the bottom.
Next select equation lines by clicking on the row number. You can use standard Windows ctrl-select or shift-select methods for selecting multiple rows.
After your rows are selected, click and hold in the row number area of one of the selected rows. Drag your mouse pointer up or down the rows. The insertion row will be noted by a red line between the destination rows. Release the mouse where you want the equations dropped.