Complex sentence: Subject-matter experts are welcome on Wikipedia, particularly within their areas of expertise, subject to the guidance on, and while making sure that their external roles and relationships in their field of expertise do not interfere with their primary role on Wikipedia.
Split into simpler sentences: Subject-matter experts (SMEs) are welcome on Wikipedia, particularly within their areas of expertise, subject to the guidance on. SMEs are expected to make sure that their external roles and relationships in their field of expertise do not interfere with their primary role on Wikipedia.