Try giving it 5 or 10 turns clockwise until the direction of movement becomes obvious. By attaching a long strip of wood to the motor carriage the movement at the end of the stick will amplify the carriage movement.
Also, knowing how many fractions of a degree each turn gives you is useful for doing precision work. You can zero on the perfect cut.
To determine this you need a square, a thin block of wood that is thicker than the saw teeth, a straightedge and some drill bits to use as a measurement. Numbered drill bits come in handy for diameters less than 1/16".
Describing it is more difficult than doing it.
If you have a sci calc. or spreadsheet you can figure angles from the rise:run using the arctangent function. The trick is to make sure your answer is in degrees and not radians. A radian is 57.3 degrees.
E.g., if the edge of an 8" blade [radius 4"] is off by 1/16" [.0625"], the angle is arctan (.0625/4) = 0.895 degrees, and inversely the tangent of 0.895 degrees is .015625 = .0625/4.
A factory miter cut might be 1/64" off out of 8".
Another way is to clamp this
onto the blade and check that the ruler part is parallel to the saw bed, then use the arctangent to check the angle if it is not 0.00 degrees. Measure down to the bed from each end of the ruler part - then your span is 12" and 1/16th out would be 0.298 degrees.
The head of this square is 4.3" so for your 210 mm blade you will need a shim 1/8" thk and 3" lg or so between the blade and the head surface so the head clears the tooth offset, otherwise the head surface will not be parallel to the saw blade surface.