Combine and Unpivot Tables Multiple Worksheets Power Query Function

When you have multiple worksheets or tabs to combine together, it's not a difficult process to copy and paste. However if you need to transform the table in those worksheets, like unpivoting it; still is not that bad albeit it'll take a bit more work to transpose the columns and rows. Now if you had to do this to a LOT of worksheets or if you had to do this on a recurring basis, it becomes a pain to do this. The solution is to have Power Query automate these steps; and it can future proof it by incorporating new data.