Please show me the steps to solve this forecasting spreadsheet.

$1.$ What is the forecast for period X using forecasting technique Y$?$Example: What is the forecast for period $8$ using the $3$ Period WMA Forecasting technique where the weights are $(0\mathrm{.}5,0\mathrm{.}3$ and $0\mathrm{.}2)$

$2.$ Using data from periods $1$ through $16,$ what is the X error measure for the Y forecasting technique?Example: Using data from periods $1$ through $16,$ what is the MAD for the $3$ period moving average?$$

$3.$ Using data from periods $1$ through $16,$ what is the best forecasting technique according to the Y measure?Example: Using data from periods $1$ through $16,$what is the best forecasting technique according to the MAD error measure?