Hi Maty and welcome
You’re in the right place. I’d say you start by picking a date and working up to it in your head and in your actions. Mentally start planning what you’re going to do for the first 2 weeks, and have a ‘go to’ plan or activity to start doing as soon as you feel bored. In terms of your actions, have all of your crap food gone by your start dat and cupboards filled for a week, so you know you won’t have to go shopping and there will be no unhealthy options at home. If you can be single minded for a couple of weeks, the rest gets easier. It’s so much easier to keep going than it is to start but pick something you think is realistic to stick to. Good luck!