basically my good man, take the chain off the chainring, wrap it round the cog in such a way that the chain is overlapping and engaging with itself, and then twist the wheel till all the slack in the chain is taken up. Then keep twisting till the cog comes off. You just need to figure out which way to twist. I am that way retarded and cannot figure it out without actually doing it, and even then i get it wrong. ;)
see here for pictures and everything (google is your friend!)
basically my good man, take the chain off the chainring, wrap it round the cog in such a way that the chain is overlapping and engaging with itself, and then twist the wheel till all the slack in the chain is taken up. Then keep twisting till the cog comes off. You just need to figure out which way to twist. I am that way retarded and cannot figure it out without actually doing it, and even then i get it wrong. ;)
see here for pictures and everything (google is your friend!)