The placement of the buttons in iQ-POS is set by using the "Move Buttons Around" function..
Log into the POS terminal mode, like you are going to enter a check and click on Functions
Next, select Move Buttons Around
Once you are there, click on the menu group for which you want to rearrange the buttons and that will open up the screen with the items. Simply click on the item you wish to move and then click on the button you wish to move it to. The button will move to that new location.
When you are done rearranging all the buttoms, simply press Functions again and the button placements will be saved.