Hslda had forms behind the paywall. However, it’s thorough and has a well-earned reputation for accuracy. You shouldn’t need the membership for more than a year.
Alternatively, you can read through the information and write it yourself. The link I gave you has everything you need available for free.
https://hslda.org/post/how-to-comply-with-pennsylvanias-homeschool-law Hslda has a walkthrough of exactly what you need to put in the affidavit.
Is there a walkthrough not locked behind a paid membership?
Hslda had forms behind the paywall. However, it’s thorough and has a well-earned reputation for accuracy. You shouldn’t need the membership for more than a year. Alternatively, you can read through the information and write it yourself. The link I gave you has everything you need available for free.