R33 headlight

Sorry if this question is stupid. How do I replace the low beam headlight bulb? Do I need to take out the whole headlight? or can I just turn the knob and somehow take it out? I can't figure it out. One more.... all I need is the H1 bulb right? not the whole case deal with a bulb already inside it??? Please get back to me asap, I've already got a ticked for a headlight out! Thanks.