when you launch the app, tap on the clock in the left hand corner to set the timer speed.
i have mine set to 3 seconds because 5 was just too long.
after you set timer, it instructs you to tap the screen to start. it will count down from 3 seconds, then take a picture. this process is repeated 3 more times until you have taken 4 pictures.
the pictures are in color by default on this app but if you slide the circle down the blue bar, you can change it to black and white!
after you've decided whether you want color or black and white tab publish and it will bring up a list of options to chose from.
i always just publish mine to my camera roll and then i share them on facebook or twitter later, if i want to.