Go to System Settings → Users and Groups → click with two fingers on your user, select Advanced settings.

here check User name - that is real login. If you don't like, it's better to create new user

Open System Settings, click at the top on user. Enter login and password of your Apple account. After that enter 2FA code from SMS.

And after that Apple will require you to enter password from one of your old computers! Be sure to have old computer nearby if you can! Do not wipe it before you setup Apple user on new computer!

1. Open Safari
2. Menu Safari → Create Profile..
3. Click Start Using Profiles

Now configure at least 2 profiles: Work, Personal

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

First install CLI tool mas:

brew install mas

Now you can search for programs with

mas search nicetool

Install programs with

mas install <app-id> ...

list of useful programs and app-ids:

Homebrew