Very simply; Strike and conversion price are the same thing, different words. You pay 2c now for the option, that gives you the right to, by the expiry date, convert it into a share (head). To do this with POKO you pay 20c to the company. So 20c + the 2c you paid for the option = 22c for a head, they are currently at a discount as the heads are at 24.
DO NOT BUY POKO if you needed this to be explained to you, it is a very high risk/reward affair. The only caveat to this is if you planned on buying POK now anyway it's a great way to get a discount and not have to pay up for a few weeks, but make sure you have the cash to convert.
POK Price at posting:
24.0¢ Sentiment: Hold Disclosure: Not Held