I will skip conversation pointers, as those choices are entirely up to you. As with the previous episode, I won't post guides to chapters with only talking.
After some talking, you'll find yourself amidst some
zombies sorry, walkers. First you have to save Kenny and then you have some walkers between you and Clementine.
The walker grabbing Kenny can be disposed of by a simple headshot. As with the walkers between you and Clem, the best thing to do is shoot the ones near yourself so you won't die. One of the zombies near Clem can't be shot and Chuck has to help her out, there's nothing you can do about that. I've checked and there are really only two walkers close enough to you for you to have to shoot them, before Chuck comes the rescue. After a cutscene, you'll have your first achievement.