If you're coming from npm, the main changes are:

• Running yarn is enough to run an install! It's an alias to yarn install.
• Adding or updating a dependency to a single package is done with yarn add.
• Upgrading a dependency across the whole project is done with yarn up.
• Your scripts are aliased. Calling yarn build is the same as yarn run build!
• Most registry-related commands are moved behind yarn npm (ex: yarn npm audit).

To see the full list of commands, check the CLI reference.