My first 8 hours in Subnautica - advice welcome

I am playing Subnautica for the first time on PCVR - what a game! The world is huge and I am having an amazing experience each time I play, discovering something new and making progress.

Here's what I have done/experienced so far. I'd prefer to ask on here rather than google everything. Spoilers of course for anyone who is only starting out:

  1. I have built my base right beside my crashed lifepod. I did this because I only had solar power available but now I am starting to unlock more power sources I might consider moving. However my base is a single room filled with lockers (why I built in the first place). Am I better creating a 2nd base or any tips for how I can deconstruct and move everything (including all the resources in the locker)?
  2. I have a compass but I have no way of measuring distance - so when clues say search X meters away from this landmark I struggle. Will there be something to help with this later on?
  3. I am struggling to understand the different areas - from reading on here and other places they all have names. Do I need to start mapping these out myself or will there be something to help later on?
  4. I am convinced my Seaglide was showing some sort of landscape map for a brief time but I don't know how to get this showing again.
  5. I have discovered some sort of portal on the island with the mountain. Once powered up it transported me to the other island, however at one point I seemed to materialise in mid air and I fell to my death. Was this intentional or a glitch?
  6. I am getting very frustrated with the giant leviathan destroying my Seamoths - I have lost 4-5 of them. I have just unlocked vehicle upgrades but I am still searching for blueprints to complete the moonpool. Will these upgrades help or any other advice for making sure my vehicles don't keep getting destroyed (or is this just part of the game experience)
  7. Lastly - some strange blue image appeared in front of me with a voice that said something like "what are you". No question here - just that this game is incredible when it comes to mystery and discovering things like this!

Any other tips at this stage are appreciated. I am just loving exploring, I haven't ventured too deep or gone into too many caves yet except when I am resource hunting for something specific.