Check the angle against the old bevel. If the new scratch pattern is on the back edge of the old bevel, you are lowering the angle. If it is at the edge, the angle is being increased. When the scratch pattern is centered on the bevel you are duplicating the original angle. Keeping the original angle is a safe strategy until you gain more knowledge.
Black marker helps show the honing angle, here with a rod-guided system.
If you can't see the scratch pattern, try darkening the old bevel with a black felt tip marker, then stroke the stone again. The scratch pattern will stand out against the dark marking. When the angle is set correctly, grind one side of the blade until you have removed the old edge. Grind until you have raised a burr. The burr will appear on the side opposite the one you are grinding.