Soak it overnight then simmer it until it turns soft. Then soak it for at least 10 days in a warmish place. You can add yeast, but the wild yeasts in the atmosphere will invade the maize and fermentation will take place. At this period use it on the hook hair rigged.
I warn you the aroma and fumes from the mix might send you a little ga ga. No driving after preparing this stuff.
But the fish, especially the carp will fight to get at it.
If you try it, let us know what you think. I'm determined to give it a try this year...been meaning to for ages.