Hey! I find it hard to explain well as there’s so many bits to llw depending on what the dog is struggling with, and I’m not a trainer although I have helped others and trained my own dogs to llw. I’ll include a link to a trainer called KikoPup - she’s really good at breaking these things down and the video is very long but you can skip it to the bits that are relevant to you/answer your questions! All my girls I’ve used food with at least to start off with, now all mine (youngest just turned 2, eldest 11) don’t pull. The only time we ever need a refresh is if we haven’t done llw for a while or if they’re in season, I think it’s also really valuable for your dog to be able to sniff on the lead without pulling - personally I’m not in to a strict heel at all times, again kikopup also does this. You may need to drive to parks whilst working on llw so that you’re not reinforcing his pulling, usually with what you’re describing it means that the dogs been used to pulling to things it wants or exciting things
Best of luck! I think llw is honestly one of the hardest things to do but it has the most pay off for sure! Also with training never be afraid to look like a fool (in some peoples eyes!) I trained all mine on a lead since around 12 weeks consistently, labradors can be strong as hell if they learn pulling gets them places

, and the best way to engage any dog is to be fun and offer lots of praise amongst the food - it may be embarrassing at first to be speaking to your dog in such an animatedly way but trust me it will work if you keep up with it and are consistent with training.
https://youtu.be/EK6PZ5l-3lI?si=l8dCeHccWN5PyshF