/24 is a 256 host subnet, so you can have 1-254 (0 and 255 are special) in the last "octet" (each section of an IP address is denoted as an octet).

You can play with the numbers here [0] to see valid combos, like this: 192.1.254.19/24 (or use a 255.255.255.0 subnet mask)

0 - https://www.calculator.net/ip-subnet-calculator.html?cclass=...