Help With Garruk's Horde Ability

[crystalkeeper]

I know how the ability works and all, but I cant seem to get it to work in forge. In the card text it tells me what the next card is, but then I dont know how to use it if its a creature.

Thanks,
CrystalKeeper

[Marek14]

Click on the flashback icon (lightning bolt) on your panel. All nonstandard playing of cards is done from there.