That is a simple mosfet level translator.

It uses pull-ups to each voltage, to do the level translation from low side to high side, and back.

You need to connect the 5V power to the HV pin, the 3.3V power to the LV pin, and your GPIO to the appropriate pin.

The RPI has a 3.3V power rail you can use. It is fairly small in terms of current, but will work great for this purpose, as this circuit has a very low current need.

That is a simple mosfet level translator. But there are two issues, see update:

It uses pull-ups to each voltage, to do the level translation from low side to high side, and back.

You need to connect the 5V power to the HV pin, the 3.3V power to the LV pin, and your GPIO to the appropriate pin.

The RPI has a 3.3V power rail you can use. It is fairly small in terms of current, but will work great for this purpose, as this circuit has a very low current need.

Update:

Based on the reviews on the amazon page, you either get a simpler board, with just mosfets and resistors, which work as I described above, or you get the pictured one, which includes a 3.3V regulator. In that case, all you need to connect is 5V, the Gnd, and the GPIO.