The YouTube video "How to Use RANDBETWEEN Function in Excel" instructs viewers on generating random values between a given range using the Randbetween function. The speaker begins by explaining that all Excel formulas start with an equal sign and demonstrates using Randbetween with a bottom value of 1 and a top value of 100. The function is then dragged down to produce additional random values. However, the speaker cautions that every time the Excel sheet is opened, new random values are generated. To maintain the existing random values, the speaker recommends copying and pasting the generated random value as a fixed value to prevent new random values from being generated each time the sheet is accessed.