Well since I don't have a PPS I can only assume they are similar to the P99. There is no tool with the P99 either. You need a small screwdriver and the screw would or should be on the right hand side of the sight. There would be a small plunger that will depress when you turn the screw...adjust windage accordingly. If this is not the set up for the PPS you will have to wait on someone who owns one to post...
"The PPS sight is drift adjustable. Drift adjustment is done with a hammer and a drift punch.
Sorry about that, but there is no screw or anything to assist adjustment for windage."
There is a T-cut at the rear sight channel, that is to facilitate the installation of the rear sight, sliding it from right to left. I have a close-up picture for that, but too large and unable to upload here.
This rear sight has a special roll pin it it that has a serrated edge unlike regular roll pins that have a staight cut groove in them. The sight was installed (probably by a machine) that compresed this serrated groove roll pin and slid the sight on sideways in the T-cut channel. The roll pin then expands slightly and the serrated edge digs into the bottom of the T-cut channel holding the sight in place. So to move it, you will need to drift it over with a soft brass or aluminum drift.