Hi there and welcome
What have you tried so far (in terms of motivation)? And what was the thing that made you fail and/or it not work so well for you?
Basically you're right, it's pretty simple. Exercise and eat well. Done. Simple right? Yeah...
It's all about baby steps. Making a positive change to your lifestyle every so often that you can stick with for the rest of your life and little by little you've made 10 changes after a month, and maybe even 100 changes after a year. Simple things from what you decide to put in your shopping trolley, to how you plan out your meals for the day, to how you put aside time for exercise, what you do to keep motivated to want to exercise etc. there is a lot of good advice out there and a lot of bad advice.
The simplest concepts to stick to are (in no particular order):
-you're making a lifestyle change that you will stick with for the rest of your life. There is no dieting. Dieting = something you stop. Lifestyle change = forever.
-there are no shortcuts (you already know this one!)
-exercise! (cardio = good!) but you'll want to mix it up and pick something that you enjoy. The best way to make sure you keep doing it is to exercise with someone else. E.g. play squash or go bike riding with someone. If you can't find anyone there's no need to feel worried (I personally enjoy exercising by myself as otherwise i'll feel embarassed about looking like an idiot running along the path panting like a big fatty while my mate coasts along wanting to go faster...)
-energy in - energy out = net energy (any excess and you'll gain weight, any non-excess and you'll lose weight)
-doing weights / resistance training is good as at any level of training (even the most piddly weights) prevents you burning both fat + muscle and focuses your efforts on any fat by promoting muscle growth. i.e. you eat less and/or exercise getting a net negative energy total for the day, your body loses water, fat, muscle etc. but by having weights built into your weekly schedule you'll be promoting muscle growth. Then protein in your diet will be converted into muscle growth and a greater % of your weight loss will be fat rather than muscle. [or at least this is my explanation of why weights are important]. The additional benefit of weights is by increasing muscle on your body you are increasing your resting metabolism (which is the bigger energy consumer as a total % of your daily energy consumption than any cardio you do unless you're in the tour de' france or something).
-eat healthy (you already know this one as well!), however I guess the most important thing is to make changes you can stick with, if you make mistakes don't give up, give yourself a meal a week to cheat or whatever works for you, that way you can say that you'll make a healthy choice on monday night as you know that
on friday night you're going to have that dish you wanted.
-drink LOTS of water, minimum 2 litres a day. If not 3 litres +. It won't kill you. Half the time when you think you're hungry, you're actually just thirsty.
-take vitamins: pretty simple just get some of those multivitamins, and some omega 3 tablets and some probiotics. done.
-take time to relax
-sleep is really important and can be a big reason why people get no where. I have sleeping issues myself which have tended to thwart my lifestyle overhaul. But i'm aware of it, so I plan and make strategies to deal with it which seems to be working for me.