A multiple of a number is just the product of the number and another whole number. So the multiples of 36 are 72, 108, 144, 180, and so on.
If you have two numbers their least common multiple may be the product of the numbers, or it will be less than that if the numbers have a common factor. The LCM of 5 and 36 is 180, but the LCM of 36 and 24 is 72, because 36=2*2*3*3 and 24=2*2*2*3. Their LCM is 2*2*2*3*3=72.