Scout the area, Ride the grind rail, and Buy Deserter's Infobot are a series of missions in Ratchet & Clank. Upon landing on planet Batalia, Ratchet and Clank automatically started with the "Scout the area" mission in their log, which promptly completed itself when they found a grind rail. Upon completing the "Ride the grind rail" mission, they found a Deserter, who requested 2,000 bolts for "bus fare" so that he could return home. Upon paying him and completing the mission "Buy Deserter's infobot", they also received an infobot for Gaspar.
Finding the grind rail is easy, as it is located directly at the end of an upwards leading slope, found to the right of the landing pad and past a series of buildings. This grindrail is actually a very short loop that automatically deposits you back at the start. Instead of simply riding it to the end, you must use and to jump from one rail to another. Meanwhile, you must dodge obstacles, gaps, and mines by jumping, though the latter can be rarely shot with the Blaster if the angle is right.
In general, always switch rails when prompted, as staying will often lead you to repeat the same section. Halfway through, mines become the most dangerous enemies, and although one is easy to avoid, it becomes troubling when they are placed shortly after another, or appear in a cluster. The angle of the camera view and Ratchet's high speed can make it difficult in some sections such as when Ratchet travels at a steep upwards angle to accurately predict when you will need to jump.
Eventually, you will go through a mountain and automatically leave the grindrail, landing on a lone platform with the Deserter, completing the second mission. Pay him the requested bolts to receive the infobot and complete the third mission, allowing you to use a teleporter to return to the starting area.