This should be quite easy to explain. So the first thing you want to do is multiply them. This isn't to hard if you know your times tables. Don't worry about the decimal till the end.
15.37 × 5 --------- 76.85
15.37 times 5 is 76.85
Now on to the decimal. All you need to do is move it two times to the left. You see how it's in between the 5 and 3? The same goes for your answer. So it is 76.85
I hope this helped!! ^^ I can make this a little more easier to explain if you want me to just in case, ok?