Best endurance in a fixed pitch:
Fly LOW, with minimum drag configuration, use the lowest power setting that keeps you airborne (the speed will be at or close to minimum descent speed in a glide), lean for peak EGT or - even better - lean of peak.
If variable pitch prop: use the lowest authorised RPM with whatever MP is needed to maintain the speed.
Best range fixed pitch:
Min. drag configuration, leaned to peak EGT or - better - lean of peak, high enough that full throttle is needed to fly at best range speed (same as best glide speed.)
If variable pitch prop then use lowest authorised RPM and an altitude that requires full throttle to maintain Vg.
Some notes:
Min drag config: Flap, gear & cowl flaps up. Flown in balance with heading & altitude flown accurately.
Lean of peak: To maintain the same power % as a given Rich of Peak setting will require the throttle to be open a bit more say, 2 or 3" MP or a hundred or two of RPM (approximately). If you're already at full throttle then you may require a slightly lower altitude for more MP or RPM to make up the power lost from setting LOP.
If there's a head or tailwind then a power vs speed curve is useful for finding the Best Range speed. Adjust the origin of the best range tangent to the left for tailwind & right for a headwind. Amount to adjust is the same as the head or tailwind component eg 20 kt headwind then adjust the range tangent to the right by 20kts.