It’s important to start on the same page, so here’s a breakdown on how we may differentiate the strings on the guitar by numbering them.
The smallest string is the 1st string. It is the string that’s closest to the floor when you are holding your guitar.
The largest string, or the string closest to the ceiling when you are holding the guitar, is the 6th string.
So, if you make a logical jump, you’ll realize that the strings in between are just numbered 1-6 as in the picture below: