Evidence is really important, as the Proctors will primarily determine your complaint outcome based on the statement and evidence you put forward. Whilst they do open an investigation, this is primarily to hear the universities response to your complaint, rather than finding additional evidence to support your complaint.
For each piece of evidence, you should rename it as the Annex number it is, and a brief description. E.g. Annex A, email from Head of Department. On the form, for each piece of evidence you are providing you should give a brief description, explain who authored it (e.g. yourself, your doctor, your senior tutor), the date it was created and how it is relevant to your complaint. For example, does it prove that you attempted stage one resolution? Does it show a process wasn't followed correctly?
To make it as easy as possible for the Proctors to understand the relevance of each of your pieces of evidence, in your main statement when you are explaining something which is evidence, you should write (see: annex xyz).
If you have more than five pieces of evidence, then you can add additional rows. However, be careful to ensure that every piece of evidence is complete, relevant and proportionate. Therefore, be concise in what you are presenting whilst ensuring the whole picture is showcased.