Don’t listen to nomad; that’s no advice.
Well, it depends how deeper you want to go. A little bit more information would be useful, for example, which is your current setup?
I think a good start is to delete BigTech’s social media, switch to Firefox, start using uBlock Origin, uMatrix, HTTPS and some other add-ons. Installing F-droid on your smartphone and starting to switch your applications and services for open source and privacy respecting alternatives, for example, Protonmail as your e-mail provider.
