Assuming the device on the right is the leds, there currently doesn’t appear to be a level shifter in the circuit. If you have to use the txb then this circuit should do what you want (you may need to ground the unused terminals on the txb). VCCa gets 3.3V from the PI, VCCb gets 5V from the led string. If the load is low enough this may work successfully. You probably want to only drive 1 led input with the txb output as load is what breaks them.
I grabbed the Fritzing part for the txb0108 from the adafruit frtizing library (google will find it) as it isn’t in core parts. Basically the yellow and blue wires from the PI go to the A side of the level translator and the same output pin on the level shifter on the B side goes to DI and CI on the LED device.
Peter