Start with altitude, and make sure it’s armed to capture. You might have to press the ARM/ALT button a couple of times. Press the lower button to get to Alt select mode, dial in your altitude, then press the same Arm/Alt button again to arm the desired altitude capture, then press the knob to engage vertical speed, and adjust as needed. It works sensibly in this way. I agree the other VS/ENG mode button acts a little weird but I haven’t really needed it.