I played through the tutorial and completed it. For the final part it is enough to do basic actions to increase the mood and then you can do advanced actions to increase the relationship depth. You can see what the depth is from the green bar above the NPC character. It is similar to a health bar but instead of decreasing it you act to increase it. ;) 
After you click OK there is a bug which causes an endless loop. Just reload the page and you will be able to start the game.