If you are unable to find the property you need in the "Create schema" page, you can find it in the "Add Subschema" page. This is because some properties are actually other schema types. For example, the "founder" property of an "Organization" schema is of the "Person" schema type. To add the "founder" property to an "Organization" schema, you must create a "Person" schema as a sub-schema. This allows you to accurately describe the relationships between different entities on your page.