The Looperboard is a powerful device that allows the recording of 4 simultaneous audio or midi tracks; and naturally when dealing with Midi a lot of users will want to sync up BPMs from external drum machines, ARPs, or DAWs to get all their devices on the same page. This article will explain the changes in your setup that needs to be made to accommodate using an external midi clock.
To set up your Looperboard to a device with a midi clock, you can connect through either the USB A ports or Midi 5 pin connection on the back of the unit. From here, you're going to want to go into the Global Settings, tap the Midi Tab, and let the unit know where the clock source is that you want to pull from(5 pin or USB) and turn on the Midi Clock sync. From there, you're also going to want to turn on External Midi Control so that the clock start messages can be received and the Midi Thru if you have another device you want to send the clock to via the Looperboard's Midi Output.
One last note on setup: While for the vast majority of devices the Midi channel can be set to Omni and you'd be fine, some devices may require you to have a specific channel setup for their transport controls. Please review their setup guides for more information if they have HUI controls.
For the Looperboard, giving an external device control over it's clock means that functions of the clock are now being given to that external clock source. Because of that, your footswitches cannot start the clock and thus cannot start Recording. As stated in the manual, what you should be seeing is a red blinking light when this happens, this is a sign that your track is record armed and is now waiting for a midi start signal to start the synced up clock for recording. This will have to come from your midi device, so if you are going to still want some kind of control over recording from your feet, then you're going to want a midi footswitch controller to go into your clock source setup to send CC message to start the midi clock on that source, and have that signal pass to the Looperboard to start recording. Please consult the manufacturer of the external midi clock to find that CC message.