brand new Prime hatch not opening.

Hit the unlock button on the fob twice to unlock all the doors. Similar to all the other cars with remotes. But I think this can be changed by the dealer. (I'm just going from memory here and assuming all Prii in this generation are similar in this regard.)

The hood opens like most cars. Pull the release at the bottom of the dash near the driver's left knee. Then finish the release by sticking your fingers under the center of the hood and pulling the lever located an inch or two to the driver's side of the center. Again, just like most cars. Nothing special or secret.

I'm not making fun, but this is all described in the owner's manual. If you're struggling with stuff that's similar to most vehicles, you will really want to read up on the stuff that's different. This is a fun car to drive, but it's even more fun when you know how to take full advantage of its features.

These are from my manual. Yours would be similar. I recommend getting the PDF version from Toyota's owners' web site. Toyota Warranty & Toyota Manuals | Toyota Owners

 

Which trim of Prime is yours? Your profile says 2020 Prius Two Eco which is not PRIME. For LE model, SKS works only on the driver side door, but for XLE and Limited models SKS works on the driver side and the passenger side front doors as well as the rear hatch. On all three models, the fob lock and unlock should work on all five doors. Depending on the way the fob was configured, the first click will unlock the driver side door only, but long press or double click should unlock the rest of the doors. If the rear hatch is not responding to your fob, the sensor might be faulty. There is procedure to unlock the hatch door manually. from inside of the car.

Hood can be unlocked by the lever under the dash left side of the steering wheel as shown by @jerrymildred .

 

If you unlock with the "clicker" but do not open any doors within some short specified time, the car will re-lock automatically.

 

Yup, 30 seconds.

And I noticed it doesn’t respond right away to unlock it again via the door(s). Have to press the unlock button on the hatch twice in some cases. Might be a timing reset issue because if I wait say 10 or so seconds it’ll work like the first time.

iPad ? Pro

 

That's almost not an exaggeration.

 

Toyota has a PHD program for new owners. I'm in my 3rd year. Still finding new things about the car.

 

For the hatch find the hidden button, hold it down, lift the hatch. The hidden button is right where you'd expect to put your fingers to lift the hatch. If the car is locked you'll need the fob nearby.