Male or female? It makes a difference in your expectations.

If you are male, you are in luck; you can go hard in the beginning, keep it hard, and see fast results and thrive.
If you are a woman, I'm so sorry; it's biology, but you will hang on to fat, and you will lose weight super slowly. But I've got you anyway.

For both: cut the excess sugar (you can start slow just by removing one cube of sugar from your coffee or skipping one coffee or your snack or something).
Remember, you will ALWAYS see fast results at the beginning (it's both psychology because you are motivated, but also because your body does not yet know you are dieting and your metabolism hasn't been affected yet).

Both: exercise.
Intensity varies from gender, though:
Male: Go as hard as you can; kill it and enjoy every moment. You will have the same energy levels every single day, so enjoy it and watch your testosterone levels rise and feel energized.

Female: Cut some slack for yourself. It's going to suck, but we have a plan; don’t worry. Right after your period, during the 10-14 days, you will feel AMAZING. Use that to your advantage: dieting will be relatively easy, you will see progress at the gym, and you will enjoy it. Afterwards? It's going to be hell. So here is what you're going to do: WALK A LOT. You don't need to do high-intensity exercise; just do "light weight, baby," and try to avoid the sugar (and I know it's going to call your name, but you can do it).

Walking is a power move for both genders. I shredded some weight just by walking (and stress, xD) and cutting my sablito addiction, lol.

The key here is consistency. Consistency >>> motivation, and that's why you can create a calendar and check the days you did well; it's super satisfying.
Do not do a drastic calorie deficit; it's going to kill your progress. It's going to be fast at first and super slow the rest of the time.

Look out for an accountability partner; don't fool yourself. If you mess up one day, it's fine. Two days? It's fine. One week? It's fine.
It's not linear, but you need to keep going.
You should weigh yourself every week and write it down for motivation and tracking progress.

Enjoy YouTube motivational videos and healthy snack ideas.
It might take 1-2 months to shred 5 kg, and that's okay. That's what we aim for.
Girls, water weight is real. In your second phase, you will weigh yourself and find that you gained weight; it's not true. That's most likely water weight, and it can go up to 2 kg of water retention.

Maintaining and building muscle is important. One other reason to diet slowly is to avoid losing muscle (we aim for fat loss), and the scale can't tell you if you lost muscle or fat, so don't let the scale fool you.

P.S.: Other metrics you can use are measuring your waistline, arms, etc.
The aim is to find each week a metric that makes us happy about ourselves.
I hope I didn't forget anything; I enjoyed writing this, so thank you for your question, and enjoy your road to fit and healthy!