If you have ordered the Kewlus Cobra Bag kit that includes the Multi Base, the best way to set it up is to make a baseboard for it.
Making a baseboard is quite simple - all you need is a 1 inch thick particle board or chipboard that is roughly 2ft x 2ft in size. Although the Kewlus Multi Base comes with 8 self-driving screws, they are primarily designed to be used with the Platform Paddles. I recommend getting 8 countersunk wood screws based on the combined thickness of your board and the Multi Base (0.63 inches thick). For example, for a 1 inch board you could use chipboard screws up to 1.63 inches long.
If you can't find a thick enough board, you can simply glue together two thinner boards (like I did) to make up the thickness. The thicker the board, the longer the screws that you can use. Longer screws will give you a stronger connection of the Multi Base to the board. A thicker board will also weigh more, thus providing extra weight and stability.
Note, I have rounded the corners using a jigsaw and also cut out a handle hole for convenience. You can also paint it your favourite colour!
Watch the video to see it in action with the KS3 spring: