You will need a file called myschema.xsd or something similar. There will be a reference to this schema file in the manifest.xsf (as seen below).
I have an example of a simple schema file below.
The schema file has references to two attributes: “Form” and “UniversalID”. These are not required.
The file will have a section with a name of “myFields”. You can use a different section name; but you will need to reference it with the correct name elsewhere in other XML files. The field names will be listed in a subsection here. Note that “ref” is used to identify a fieldname with “my:” in front of the fieldname.
The next sections identify properties of the fields. “Details” and “RelatedDocuments” are like rich text fields. Both of these have special properties. The remaining fields are either of type “string” or type “date”. Note that the type definition also includes “xsd:”.