Select top left cell, format as table, make sure "my data has headers" is checked.
Click just below the header row to select and entire column of data (excluding the header row). Format as you please, validate as you please. You can even right click, insert a new column, then create a formula that verifies the data and outputs nothing when it's good and "OHSHIT" when it fails verification. Then you can non-destructively filter your table on "OHSHIT".
If you're using Excel at least learn to use it. This shit is up there with people who hit Enter/Return twice to generate a blank line in Word.