Hello and welcome!!
Start off with small changes you can stick to, like just keeping track of what you're eating, not worrying so much about a certain plan right off the bat, but getting in the habit of knowing what you're taking in, it'll be easier to make adjustments if you really know what you're eating.
What has always worked for me is building a foundation of exercise, because I like to eat, exercise is a very important part of my plan. Again start off slow, just maybe some walking, and mark that down, too, if you do end up somewhere like weight watchers you'll already be in the habit if tracking what you're eating and your exercise.
Most important if you fall off your plan, just get back on it, there's no failure, everyone has setbacks, but if you end up eating well and being active more times than not eating well and being active you will be successful in the long run.
Like Jacqui said, check around the site, try something, if it doesn't quite work for you try something else, keep doing what does work and you'll develop your own plan for a healthy lifestyle.
Wishing you the best