A harness does not stop pulling. It changes what pulling does. Front clips turn the dog, back clips let a dog lean in.
Front clip
The leash attaches at the chest. When the dog surges, the body turns toward you. Good for training loose leash walking, less good for dogs that need to pull, like joggers' companions.
Back clip
The leash attaches between the shoulders. Comfortable, hard to escape, and it lets a strong dog use its whole body. Fine for a dog that already walks well.
Fit
Two fingers under every strap. The chest plate should sit below the throat and above the shoulder joint so the shoulders move freely.
