Get 4x M3 x 20mm standoffs – female to male. These are available in an assortment kit purchased from Amazon.
To make assembly easier, go ahead and fasten a M3 x 6mm flat head screw into each standoff. Do not over tighten.
Insert the standoff with the male thread going in through the tab on the PCB mount. Guide the thread into the heat set insert on the case. Fasten the screw to tighten the standoff. Repeat this process for the remaining mounting tabs.
With the standoffs now installed, you'll need to remove the flat head screws from the standoffs. While holding the standoff, begin to unfasten the screw. The tray for the NeoTreliis PCB will be fitted on top of the standoffs so the screws need to be removed.
Double check and make sure the standoffs are tightly fastened. In the next pages, you'll panel mount the remaining components and complete the assembly.