We would need a schematic, several very clear gutshots and complete specifics of the Wiring code used throughout the pedal before suggesting a potential Wiring Guide.
True Blending would be much more complex as you would need to wire it in parallel with the original circuit and determine the Phase of the original circuit. A series off/on Wiring would be easier by comparison.
An easier, actual Muff circuit would be the Opamp version we call the BMPOA. If you are just looking for a simple Fuzz with one control then as Matt suggested try the One Knob Fuzz.
Before committing to the original plan you might just want to try building your own combo pedal from start to finish especially if you are a total noob as you say. There is a combo guide located on the Guides Page and plenty of excellent circuits to choose from, the Wiring of each circuit is known, schematics are available and a much higher chance of success without a “troubleshoot” scenario.