Step 1: Divide the number into separate digits:
5308 => 5 3 0 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 3 = 2
3 to 0 = 3
0 to 8 = 8
8 to 5 = 3
Step 3: Combine the filters to a string:
2 3 8 3 = 2383