I had the same problem - no instructions. By trial and error I worked out the method of setting the presets:
Note - the radio must be tuned into a station to start with.
1. Press and hold the PRESET button for about 2 seconds until the preset number displayed starts flashing.
2. Select the preset number you wish to save using the PREVIOUS and/or NEXT buttons (the display will show the preset number in question).
3. Briefly press the ENTER button and this will save the current station to the desired preset.
4. Job done!
Anthony
February 2015