To do this, you will need to change the Level Layout of the donation level.  Use the steps below to make this change:
  1. Fundraising>Donation Management
  2. Click Edit on appropriate donation form
  3. Skip to step 3 - Design Donor Screens
  4. Click Edit next to Donation Form
  5. From the selected data elements window (right window), click on Standard Donation Level followed by clicking on Save Order and Edit Selected
  6. Navigate to the option called Level Layout
  7. Change the layout from Single Column to Single Row or any other of the available options
  8. Scroll down and click Save
Please note that the Level Layout options only appear for donation levels whose form layouts (defined on step 1) are set to Standard and not Responsive.