I need help with these questions computations please teach me how you got an answer with an explanation. Thank you :) these questions are about marketing in BM. I have to get an answer for the things written below. The answer should be found using the information in the picture i attached.

I have to get Quarterly Moving Totals and Quarterly Moving Averages and Extend Computation to include the seasonal variation, average seasonal variation, random variation. and also Extend forecasting to 4 quarters of the 5th year. Lastly, Plot the trend in a line graph and interpolate the 5th year. Can you also write down the formulas to get the answers?

A1 fx YEARS A B C D E F G H 1 YEARS QUARTERS SALES ($000) 4Q MOVING TOTAL 8Q MOVING TOTAL TREND Seasonal Var 2 Ave Seasonal Var Random Var 18 24 4 3 35 5 4 27 6 2 19 26 8 38 9 29 10 3 23 11 27 12 40 13 32 14 4 25 15 30 16 42 17 35 18 5 19 20 21 22