There is a huge range of what you could attach.
Depending on what the I-statement is focused on, you could attach photos, course certificates, any signed notes or documents from an expert, a report or summary of the activity you undertook, or a video of you doing the skill(s).
Please Note:This site is for the use of Scouts and Leaders who are implementing the Scouts Australia new youth program. It is not relevant to members who are still operating on the old program.
You're most welcome to still have a look around, however!