Start it off on some rabbit skin make sure its keen for it, then some scent on a dummy, get it finding the dummy to a command even if its just around the garden (so there no distractions) when it can find the dummy on command with confidence move out into the field with the same training but using long grass, reed beds etc eventually moving on to thicker stuff like brambles. Then take it where the bunnys are and give your command when you spot one. Should all just click in time after that. Theres plenty more ways than that to get a dog going though depends what dog it is. Thats just the way iv