Sure, here are the steps to find the area of a trapezium using a calculator:

1. Measure the lengths of the two parallel sides of the trapezium. Let’s call them “a” and “b”.
2. Measure the height of the trapezium. Let’s call it “h”.
3. Use the following formula to calculate the area of the trapezium:

   Area = (a + b) x h / 2

4. Input the values of a, b, and h into the calculator.
5. Add the values of a and b together.
6. Multiply the sum by h.
7. Divide the result by 2.
8. The final result will be the area of the trapezium in square units.

Here’s an example: if side “a” is 5 cm, side “b” is 9 cm, and the height “h” is 4 cm, the formula would be:

Area = (5 cm + 9 cm) x 4 cm / 2

Using a calculator, we get:

Area = 14 cm x 4 cm / 2 Area = 28 square cm

So the area of the trapezium is 28 square cm.