How do I charge my Helix Syn Trident? Where is the power button?

Title. I don’t see a charging port on the device itself, and the small instruction booklet doesn’t specify a charging method at all. I also don’t see a power button on the device at all.

This is irritating as I really want to use the device, but I genuinely don’t see how to use it, and googling hasn’t given me any answers at all, either.