Adjust the orienting arrow (by rotating the compass dial) until it aligns with the compass needle (which indicates magnetic north).
Step2
Determine the direction you want to go using the compass needle as a reference.
Step3
Align the direction-of-travel line on the baseplate in that direction.
Step4
Make sure everything in step #2 is still lined up, and then sight along the direction-of-travel line and pick out something in the landscape that is on that line - a stone, a tree, or something else recognizable and stationary.
Step5
Walk to that point.
Step6
Repeat steps 1 to 4 until you arrive where you want to go.
Tips & Warnings
It's not easy for the human animal to walk in a straight line, so use a series of intermediate points to keep you from drifting from side to side. The intermediate points not only keep you to the one specific line you originally intended, but they also allow you to detour around obstacles and return to the original line.
Be careful and precise and this technique will get you exactly where you want to go.