To change router bits, first unplug the SM1 Spindle from Origin and remove it from the spindle mount. You can read a full description of this process here. Press in the collet lock. Using the included 19mm wrench, loosen the collet locking nut by twisting it counterclockwise.
Insert your desired cutter. Depress the collet lock and use the 19 mm to tighten the collet locking nut. Note: the maximum diameter the collet can accommodate is 1 inch (25.4mm).