You want to swap to a dual-piston caliper. By cross-referencing the "Front Fork" section of the Trinity catalogue, you see the standard bolt spacing is 80mm. This data helps you buy the correct adaptor bracket.
Choose the specific model year (e.g., 2020 or 2021 ) to get the exact parts list. Key Specifications for XRM 125 honda xrm 125 trinity parts catalogue pdf
The PDF is filled with "exploded views." These are technical drawings where the motorcycle is taken apart visually. You can see exactly which screw goes into which hole, the order of washers on the rear drum brake, and how the wire harness routes around the steering stem. You want to swap to a dual-piston caliper