Follow this steps to create schema:
1. In main menu choose "work with schemas"
2. Press button "Create" ( ) from action menu (if you want to edit an existing schema simply click on it)
3. Enter schema's name ( Keep in mind that you wouldn't be able to rename it in the future)
4. Next click to enable full screen mode.
Default schema's template:

{
"properties": {
"title": {
"type": "text",
"data_type": "anything",
"max_size": "0",
"default": "false",
"required": "true",
"placeholder": "Enter title",
"content": ""
}
},
"settings": {
"save_format": "multi",
"title": "test",
"description": "Perfect for storing a single record",
"published": false
}
}

In "properties" we declare all elements and their properties. in this example we create element with name "title". Property "type" from element title means that what hmtl input element will be used for rendering it. You can learn more about element's types in "Schema's elements" article. Property "data_type" from element title declares which type of data will it store: "anything" - for any type of data, "boolean" - for logical data, true/false "integer" - for integers, "double" - floating point numbers and "string" - for text data. Property "max_size" means maximum allowed size for stored data, 0 - will remove limit. Property "default" means default value of element, false - turns off the default value. Property "required" - true/false, declares if element is required for completing. Property "placeholder" - declares which text will be displayed in input field. Usually it is used to display some hints.

In "settings" we store all schemas settings
"save_format" - declares way of storing posts, single means access by post name and it is ideal for storing site description etc. Multi - uses ID's system for storing data and it is ideal for storing blog news etc.
"description" - schema's description. We recommend to write there about schema's usage.

7. Next click button "Save" ( ) from action menu)

Keep in mind that there are pre reserved names for elements, which can not be used in schemas: id, description.

That all! You can click button "back" ( ) to return to the schemas list.