How to pick up the walkie talkie in Walking Dead Season 2: Episode 3

It is a completley new storyline. You can read from this link-

...a game spanning five monthly episodes that tells a new story in the Walking Dead universe while staying true to the grim tone of the comic books.

Also, if you haven't read the comics yet, you really should they are amazing. The show is really good too, but it doesn't follow the comics all that well so far.

The multitool is the screwdriver. If you're told that you need the screwdriver for the generator, return to the generator and use the multitool action ("←") instead of the hand action ("↓").