Assuming this isn't a trick question, you just pull them off. The H/L switch has a cross-shaped stem, so the knob could be oriented either way ( if it weren't for the lightpipe at the indicator end). The A/C knobs are "D" shaped and have an indexing tab cast into them so they can only be installed one way. I found this out when I did the group billet knob purchase. The H/L stem did need a little pressure, but the A/C knobs went on fine.
Hope this helps.