To add a logo to a form via the Form Editor you first need to open the logo in a paint program (i.e. MS Paint, Photoshop, etc). While the paint program is open with the logo, go into the Form Editor for the form you want to edit. Then copy the logo from the paint program and paste it into the Form Editor.
The Logo may need to be resized once placed in the Form Editor. To resize the log select the logo by clicking it then drag the corners/edges of the log to increase/decrease the size. You can also drag the log to the desired position on the form.
When done press the Save button to save your selection and stay in the Form Editor. Alternately, you can press the Finish button which automatically saves the file and exits the Form Editor.