Before version 1.1.0, you would have to use the focusContentEditor method (see official docs) to manually bring the editor into focus after it is initialized. If this method is not available in 1.0.4, then you must look into what public API is available (the implementation of RichEditor should have a clearly annotated section showing the public API) or use the RichEditor ref to manually set the focus using a method like TextInput.focus()
Starting in version 1.1.0, the RichEditor component has a prop called initialFocus. When set to true, it will automatically focus the cursor at the last position of the text content in the editor.
Regardless of how you focus the editor, I also recommend placing the RichEditor inside of a ScrollView and when the editor is initialized, scroll the ScrollView to the bottom position so that the cursor is in focus and also so that the cursor is above the keyboard.
