New to this app. Left Weight Watchers

Log everything you put in your mouth, stay below goal and you will lose weight.

I don't know what "making lifetime" means (haven't done WW), but I'm assuming that means you're in maintenance. First thing I'll say is, be careful what you read here in the way of advice, there's a lot of, ah, suspect information here. I've lost 70+ pounds over the past few years and kept it off, and part of my success is due to logging here on MFP. My suggestions are:

Be careful when searching for a food here, since most of the entries in the database come from other users. You can add foods to My Foods once you find an accurate entry, or create your own. You can also use the scanner to read bar codes (one of my favorite things about MFP). You can also set up meals you eat frequently, and this feature is also useful for entering the components of recipes. If I'm doubtful about something in the database, I'll look for other sources of information to verify. I suspect a lot of people are like me: I tend to eat mostly the same things (one of 4 or 5 favorite breakfast cereals most of the time, for example) so over time logging gets easier. I probably spend only a couple of minutes a day logging, and I always reflect on the numbers at the end of the day to see what I could have done differently. I have the phone app, and use that when I'm out. If I can't find exactly what I'm having (especially while eating out), I'll add something that's as close as I can get from the DB, and figure that's good enough.

Log everything as the last person said. If your weight goes down or up, be sure to put that in because that determines your goal calories for the day. Use the reports: I find them useful to see how my macro levels vary over the past 90 days. I'm resigned to the fact that I may be logging for a long time or the rest of my life, but that's OK because it works for me. The hard part for most people isn't losing the weight, it's keeping it off. Diets don't work, making permanent lifestyle changes does work.

One other thing - get a food scale if you don't have one, measure things in grams rather than ounces or by volume, and make sure the scale has a tare setting (so you can put a dish or plate on it, zero out, and add your food to the dish or plate). Make sure you have a consistent bathroom scale - and be aware that your weight fluctuates naturally so it's the longterm trend that counts (which you probably know already from your WW days).