Visited on May 29 without charging.
The parking is indeed open 24/7. Though I didn't see anyone else parking when I went.
There aren't any directions inside. The chargers are at the end of the row at the lowest level after the entrance, P1. There's no way to see them from the fork, and there will be little chance of spotting them from afar when cars are parked.
It doesn't seem like there's any ticket reader or code to get back in when the store is closed. The staircase to the parking is simply left open.
The ticket machines are outside. I was unable to validate my ticket at the machine closest to the wall. It would say the ticket is damaged. But it worked fine on the other machine.