Here are the step-by-step instructions on how to use the mulch calculator:

1. Enter Area Dimensions: If you have multiple areas where you plan to spread the mulch, begin with the first one. Input the length and width of the area in the provided fields. If the shape of your area is irregular, try to approximate it to the closest rectangle and measure the approximate length and width in feet.
2. Enter Mulch Depth: Input the desired depth of the mulch layer you want to spread in the "Mulch Depth" field. This measurement should be in inches.
3. Add More Areas: If you have more than one area, click the "Add Area" button to create fields for additional areas. Repeat steps 1 and 2 for each additional area.
4. Select Mulch Type: Choose the type of mulch you're using from the "Mulch Type" dropdown menu. The choices are "Rubber," "Red," and "Bulk."
5. Choose Unit System: Select the unit of measurement you're using from the "Unit System" dropdown menu. The choices are "Imperial" and "Metric."
6. Choose Area Type: Choose the type of area you've measured from the "Area Type" dropdown menu. The choices are "Square Feet" and "Acres."
7. Calculate: After you have input all the required measurements and selections, click on the 'Calculate' button.

The calculator will now compute the total cubic feet and cubic yards of mulch required, and the approximate number of bags or pallets needed. These results will be displayed below the 'Calculate' button in the "results" box.

Please note that these calculations provide an estimate. For more precise measurements or for irregularly shaped areas, you may need to calculate the area of each section separately and add them together.

Also, remember that the depth of the mulch should generally be about 3 inches for optimal benefits. The mulch calculator will not take into account variations in depth across the area.