Collectible Card Game Headquarters

Please forgive me if I'm missing something obvious, but I can't figure out how to "select target player" as requested by the card Soul Feast. I've clicked everywhere on the screen I can think of and tried every key on the keyboard, but I can't seem to get it done. Also, is there a FAQ or newbie thread to answer simple questions about how to interface with the game? Thanks.

When a card asks you to select target player, you'll want to click on the player's life total.

Thank you. That worked just fine.