Moving the supports: Left-click on a support and drag, OR change X value (for a visible support) in one of the three text boxes on the right, values that are outside of the range will be brought to max or min value (without updating the text field)

Adding or removing the supports: To remove a support right click on the support and choose 'Remove Support' in the pop-up dialog (2 supports is min). To add a support (3 supports is max), again, right-click on the place where you want to place the new support and choose 'Add Support'

Moving of point and distributed loads: For point loads, left-click on the load and drag, for the distributed loads left-click on the area covered by the support and drag (if it's a triangle then the drag effective area is a triangle). Similarly you can change the X values of the point loads. The procedure is a little bit trickier for distributed loads, top move it using the text boxes you need to change both Left X and Right X values.
WARNING: make sure that left value is smaller than then right value, failure to do this will provide wrong results for all the calculations.

Removing point and distributed loads: To remove a point load set a force to zero in a text box to the right. To remove a distributed load you need to set left AND right force densities to zero. You will see that the load disappears.

Gauges: There are 3 gauges available that are represented by red squares on the beam. You can set the gauge angles, which are effective for all gauges. You should view gauge angle fields horizontally while gauge values (such as x ,y, strain at different degrees) vertically. The coordinate system for gauges is centered on the left / vertical centre of the beam, i.e. the 0 coordinate is at the middle of the beam vertically, in the left corner, the value at the top of the beam is 'beam height'/2, and bottom of the beam is -'beam height'/2, the right corner has x value of 'length of the beam'
WARNING: there is no x/y boundary checking, make sure that the x and y values are correct by checking the height and the length of the beam, if you chose different beam or change beam length, make sure you updated the gauge positions.

Reading graphs: The scale of the graphs changes automatically when any support/load is moved or when one of the beam properties changes. The top number on the graph represents the max value, and the bottom number represents min value. The numbers have y coordinate which corresponds to the absolute min/max of the graph. To find the distance between the y-axis divisions: find which number bigger in magnitude, min or max, then divide  this number by 10 divisions. Example: max value 10, min value -12, distance between divisions=12/10=1.2

Graphing field of the absolute value of principle strain: To graph the field of the absolute value of the principle strain click 'Compute' button, it's desirable that you don't click on it more than once before you see the picture, it usually takes 5-10 seconds to compute the field.

Comparison of principle strain field with the one calculated using Finite Element Analysis (FEA):