I can't directly share PDFs, but there are free resources and tips online to help you get started with brain training for dogs. Here are a few suggestions:

1. Interactive Games: Teach your dog basic games like "find the treat" or "hide and seek." These simple games stimulate their mind and encourage problem-solving.

2. Clicker Training: This method involves using a clicker or a distinct sound to mark desired behavior, followed by a reward. It's a great way to encourage learning new tricks and obedience skills.

3. Puzzle Toys: There are free or DIY ways to make puzzle toys at home, which can engage your dog mentally by challenging them to get treats out of a container or box.

4. Online Guides and Articles: Websites like the American Kennel Club (AKC) and dog training blogs often have free brain-training exercises and articles.

Let me know if you'd like more details on any of these activities, or if there’s a specific area of training you’re interested in.