Hello and welcome!
Treats
Depending on level of distraction, many people use kibble taken from their daily rations. You can also use small chunks of fruit and meat as a healthier alternative. For convenience, many stores also sell pre-made treats. Make sure to check where it is made and that the ingredients are safe. I believe there was a chicken jerky scare a while back in the USA.
Walking
Socialisation is essential so it's important to get him out and about to expose him to a variety of positive experiences. The age in which you begin really depends on your environment and level of comfort. For example, if you live in an area with a high chance of coming into contact with parvo, it may not be the best idea to take him out without completing his puppy shots. Back when Bobby was that age, we avoided places where dogs would frequent (e.g. parks) and focused on interactions with people. We took him to the local supermarket and even carried him at times. It's a good idea to ask your vet for advice. They should know about the dangers of coming into contact with disease. Mostly, it depends on your comfort level. We avoided parks until ten days after his 16 week shot as per the vet's advice.
Potty-Training
How have you been potty-training? We didn't get Bobby fully trained until 6 months which was completely our fault but he did catch the gist of it at around 4-5 months. We routinely took him out to pee every five to ten minutes initially as he would just pee (sometimes whilst walking!) without doing any of the signs the potty training articles mentioned. No sniffing, no circling. We took him out the same door each time and made sure to throw a party (treated initially, eventually phased it out when he started dividing his pee) and added a command. Make sure you praise, praise and praise as if you have just won the lottery.
Gradually, we extended times between potty outings from every ten minutes to fifteen, fifteen to twenty-five, etc. He also did excitement peeing as well which contributed to the length of time it took to potty-train him.
Bite Inhibition
I know you didn't mention this in your OP but my gosh, this was the big shocker for me. You can read about my experiences in Puppy Biting (Sticky maybe?) and more information in our sticky, Puppy biting!. You might already be familiar with it but it is best to prepare yourself.
If you need anymore advice, feel free to ask! Lots of helpful members here and I'll try my best to answer.