After filing a civil complaint and defendant does not answer. What is the next step for plaintiff

The pleading process in civil court is very rules-driven and can be very confusing.  If you miss a step, or a portion of a step, it can invalidate what you think you've accomplished.  The first question I would ask is whether what you filed as a complaint sets forth the appropriate claims and request for damages.  It must be served upon the defendant and you must have proof of that service.  Provided that those steps were correctly accomplished, you must send the defendant a notice of your intent to enter a judgment by default (for failure to file a responsive pleading).  That notice must comply with the format set forth in the rules of civil procedure.  You may be able to obtain those form from your local prothonotary or department of court records (but many will not have those forms for the public).  You must wait 10 days after you mailed the notice to the defendant.  Again, assuming you've complied with the rules, after the 10 days have elapsed, if the defendant still has not filed a responsive pleading, you can obtain a default judgment against the defendant.  After that, the collection process (also detailed and rules-driven) can begin.  I strongly encourage you to retain counsel so as to avoid any traps for the unwary.