Here's a full video walkthrough of how to do Act 1, with three other achievements you'll find in the act, including this one (and it's timestamped).
During this act, you'll go into the basement to turn on the power. You'll go back to the surface, and use the computer to get the address of Marquez Farm. Then, before leaving, talk to the dog. Select:
"How's it going, Homer/Blue?"
then
"How about a treat?"
then
"Here's some jerky from the gas station attendant."
The rest of the dialogue won't matter - the achievement will be yours.