The method section will describe in detail how you carried out the experiment. For your appendices feel free to include screenshots.
Describe your process in detail. During a normal semester, we would approach actual students in person, but since you used a completely online approach, just describe how you recruited participants online in your procedure. For example, if you posted your link on Reddit, tell me what subreddit and what text you posted in the post (copy and paste your message into your procedure). If you posted on Facebook, tell me what you posted there. If you sent an email or text to a friend, then say you used snowball sampling by reaching out to individuals you knew and ask them if they knew anyone who would be willing to participate. The point is you want to give as many details as possible regarding the design, materials, and procedure of collecting your data.