New to this… help lol

I recently pickled red onions for the first time and now I want to try new things!! Currently working on this watermelon recipe https://www.thespruceeats.com/watermelon-rind-pickles-recipe-3059156 but I have some questions!! After I have completed all the steps (minus the canning) do I have to wait a certain amount of time before trying the watermelon? In general, are you supposed to wait before eating what you’ve pickled? Like does opening the jar stop the pickling process if that makes sense 😅 With the red onion I dug in like 2 hours later. Also, do you put the jar into the fridge once you’ve finished putting it all together or do you wait for it to cool? Does a kitchen gadget/tool exist to take things out of jars easily? Sorry for all the questions, just so new to this and don’t want to mess up especially since this watermelon took like 2 hours of my time today 🙃 looking forward to learning more about all of this!!

Ohhh also, I had the pickled red onions from Cava last weekend, which sparked my interest in all this. The batch I made is good but I’m still thinking of those cava onions! Anyone have a recipe similar to those? 😋