Range names are a very big topic within Excel. You will note they can be entered in the same box that would normally contain the cell reference e.g. "A1". This means a range name can be given to an individual cell and used in formulas in place of e.g. "A1". This means you can refer to cells by meaningful names such as "YearTotal". This can make your formulas easier for other users to interpret.
Data validation can also be used in a number of ways e.g. to force users to enter numeric values in certain cells. However, when it is used to create text lists, you can compile the list in two ways. The first is via a range name as demonstrated in the video. This is a good approach because it allows you to expand the list in future. The alternative is to type out a list in full such as "Yes, No" in the space where you would normally write "=RangeName".
If you are using Excel 2007 or 2010, then the data validation option is towards the right of the Data tab in the Excel ribbon