There are a lot of good advices, it depends on the situation you are in. For more advanced ‘retainers’, the advices differ from beginners.
In any case, I would recommend getting rid of your computer / laptop altogether, and let your parents and brothers/sisters set passwords on their electronic devices so you cannot access them.
Then buy any iPhone as smartphone (give your current phone away if not an iPhone). iPhone has a functionality that lets you block access to ALL websites EXCEPT a few that you manually have to add to a list of allowed websites. (It’s under settings -> Screen time). You let somebody else set the password. This way, you can still use your phone and access all the websites that you need. (Don’t use google or YouTube, twitch, instagram, etc as they contain semi-P material). If you need to access a computer for school, use a computer AT school or use your parent’s or one in a public library.
Now you’ve almost made it impossible to watch artificial sexual stimulation. But there are still triggers in public places. Don’t let your eyes go astray: don’t stare at women body parts. It builds up tension in your body and makes you more likely to fap.
Good luck and keep us posted about how it goes for you
