Simply type a schema name in the name field and hit Save at the top-right corner. You schema is now ready, albeit empty. What you need to do is to add your fields using the small plus icon in the top-right corner. There you will also find the Undo, Delete and Save buttons for the changes you make.
The following screen will appear:
Pick a field type (More:Field types). Add as many fields as you wish, we have added a single field of each type:
The icons circled above are present on every widget container. By default, you have 2 columns. However, you can add as many as you want, and also add horizontal rows. While technically it is possible to nest columns inside columns inside columns etc. until infity, we suggest keeping a reasonable amount of them at a time, as with each addition everything becomes smaller (scales) and at some point you will have trouble finding your fields, especially on smaller screen resolutions.
Nevertheless, you can drag and drop your fields to any container. Every field has two buttons of its own:
You can either delete a widget, or edit its information - that is, assign your values. Read on: Defining values for fields