You will want to center your piece of birch plywood on the laser using the cutting panel provided with the F1 Ultra. I used a 12in x 12in piece of plywood to make sure I cut a jig that would fit the full cutting volume of the F1 Ultra. Make sure to use the Thickness tool to focus the laser to the material, and refresh the camera so you can confirm the plywood is center.

This jig is sized to fit these style wooden keychains:
 

Ali Express

Amazon

 

If your keychains are a different size, you can delete all but one of the keychain holes, and resize it by selecting the shape and adjusting the width and height. When adjusting the width, make sure to add an additional 0.5 inches to accommodate for the tab.
 

Using the Grid array tool, you can add more rows, and space them out accordingly. With 3mm Plywood, I suggest 0.1in being the smallest gap you leave between holes or you can risk the jig breaking when in use.

I would place a keychain blank on top of the wood and refresh the camera to confirm that the sizing is accurate.

If all looks good, you can remove the blank and process the project to cut out the jig!