Sorry that this has happened to you. Fortunately, you found the defendants as now that is who they are because you will be bringing a lawsuit against them if you decide to proceed.
The court that has jurisdiction in landlord/tenant matters is the Montgomery County Magisterial District Courts: http://www.montcopa.org/index.aspx?NID=300 You need to find the district court closest to the renal property.
Because the defendants already vacated the premises, you will proceed with an action for monetary judgment for rent which is past due and the damages
to the premises. Both issues can be processed on the same complaint.
Here is the link that discusses the steps:
Please note that you can talk to the court clerk who can help you with the basics for the procedure as outlined in the link.
If you need clarification, or want to clarify your question, or have a follow up question, please let me know.