The little hex wrench included with your board fits the side fin box screws. You'll see them angling backwards at the front of each side fin box. Your board only comes with a single center fin, so you don't need this little hex wrench unless you buy additional side Futures Fins.
Paddle board fin install on SUP
Foam vent plug install on SUP
Surf fin tool: How to use
Futures fin box use on paddle boards
Paddle board shipment tracking
Stand up paddle board delivery considerations
Paddle boards shipment partially arrived
Paddle board technique overview
SUP technique for tracking
Paddle board repair instructions