First Step
Before doing anything else, the thing that you need to do first is find out if there is a Constable currently serving in your area. Every election jurisdiction in Pennsylvania is called a constabulary, and has one Constable assigned to it.
Contact your County election division and provide them your address to determine if there is a Constable serving your community.
Deputy
If there is already a Constable elected or appointed in your area, you can contact the Constable and ask if they are willing to appoint you as a Deputy. According to Pennsylvania law, a Deputy is required live in the same jurisdiction as the Constable.
PA Title 44 Section 7123
https://www.legis.state.pa.us/WU01/LI/LI/CT/HTM/44/00.071.022.000..HTM
Appointment
If the office is vacant, you may collect the signatures of at least ten qualified voters from your area and submit the petition to your County Court for review.
PA Title 44 Section 7121