How to a create new schema and/ or user

I am brand new to SQL Server Express. I am trying to create a new schema or user but to create one I already have to have the other created. I am attempting to do this with the SQL Server Management Studio (SSMS).

You will find this tutorial very usefull:

SQL Server tutorial for beginners - YouTube

This is a video to create a schema:

This is a video to create a user:

Thank-you! thank-you!