Hi Steve,
I would usually have a focus for learning walks that comes from your department improvement plan/school improvement plan. As you are new to the role and it is going to be the autumn term I would look at including seating/groupings and environment on any document to see how students needs have been considered by colleagues.
I would recommend looking at the SENCO Induction Pack from Whole School SEND also as an excellent general guide. Using the SEND review guide will help give you an overview, get to know the data manager so you can look at where students are preforming/underperforming.
Kind regards,
Cormac