Lose the gimmicks (oxygen tanks) first of all. You'll waste a lot of mental energy on things that don't work or will frustrate you.

Chicken. Fish. Rice.

Make that the core of your diet. If you're a vegan or vegetarian this obviously won't work for you. White rice is perfectly fine (just as it is in healthy long-living Japan), with this diet it simply won't matter whether you eat white or brown rice.

Ideally throw in some stray vegetables that you like (cold broccoli, carrots, cauliflower happen to be my favorites). The vegetables are sides or snacks, you never need to consume actual salads-as-meal, it's purely optional.

Stop consuming any beverages with high-fructose corn syrup in it, including all sodas (if in the US). Ideally stop drinking sugar in general, avoid sugar sweetened beverages. Drinking lots of sugar is typically one of the most common and dumbest things overweight people do.

Never consume high-calorie breakfasts, switch instead to lower calorie breakfasts (if any). I prefer yogurt, turkey bacon, or egg & cheese sandwiches. There are a lot of ways to go with a low calorie breakfast though.

No garbage snacks during the day. The little high-calorie snack fillers are weight monsters and people often don't notice them, they don't count them into their dietary problems when they're trying to figure out what has gone wrong.

Once per week you can eat anything you like. You can eat a bag of doritos. You can eat an entire pizza. Chocolate. A tub of ice cream. Consume a soda. Fast-food / drive-thru. Whatever you like. The once per week garbage day is meant to be slightly over-done (so you don't want those things for a while), it's meant to get rid of cravings and act as an outlet to consume unhealthy things. Unless you're a savage about it, you won't be able to consume enough calories in that one bad day to meaningfully wreck your progress from the other six days.

No weight lifting or working out required at all. Although I'd suggest if you don't like working out, to just go on long walks every day for the general health benefit.

Count your daily calorie intake before you begin changing your diet (for two weeks or so). Understand your body and its metabolism. How many calories do you need to consume each day to gain / lose / hold steady on weight? Then as you begin to change your diet, continue to count daily calorie intake, this is part of the experimentation process for yourself.

~1400 to ~1800 calories per day is the consistent target (depending on your height; if you're much shorter or taller than 180-190cm, adjust accordingly), and it's easily reached. You can vary that based on what weight you prefer, how strict you want to be.

If you're consequentially overweight (let's say you weigh 210lbs / 95kg and would like to weigh 170lbs / 77kg), the weight will melt off over time quite trivially. Your body won't have a choice. You won't have to kill yourself in the gym every day, you don't need to do anything special at all.

What you'll find is that there are likely just a few killers in your diet, particularly bad villains (eg soda, ice cream, pasta) that are causing most of the problem. Usually if you eliminate just a few things from your diet, you'll see a big change. The calorie counting is also meant to reveal the primary villains in your diet, they'll typically jump out from the paper after a few weeks of tracking what you're consuming.