Basic spearfishing gear

GoPro or the like, not really essential but once you get hooked in this you will want to show it to all your friends.

If I were mentoring a diver, I would ask them to dive without a gun, watch, or gopro, till they felt at ease with the first set of variables and focus on being as safe as possible and getting hooked up with likeminded MOTIVATED divers. Ie a dive buddy you can trust with your life. Establish a good one up down routine, practice it, dont get lax about this part!!! Then introduce, a polespear, then the Camera and watch. They are in my experience distractions. That will cost you fish in the long run. Dont get me wrong they have their place, but will not make you a better diver just by having them. A good buddy will help you improve with every dive. By watching and avoiding his mistakes, copying what works for him, and pushing yourself safely. YOU will improve. Pushing it alone= suicide

Tunnel vision is something a diver needs to avoid, I grew up snorkeling and swimming in the ocean, thinking of someone just getting into the sport, strapping on a weightbelt, gun, camera, watch, makes me think of that guy GOpro Theron, and outdoor catholic. Making it to a predetermined depth, bottom time, or getting a specific shoot with a camera to show your friends, adds variables on top of variables. If this thread is truly about Spearfishing and nothing else. The most important goal is to make it home safe, and get a few fish.
Begginer spearfishermen shouldn't worry about the computer or the camera.
The only concern should be your safety and your buddies. You will get more and better fish if you only concentrate on that. The rest will come in time...
Stay safe