Okay kiddo, do you remember the letter "c"? It can sometimes make two sounds.
When "c" is followed by a, o, or u, it makes a hard sound, like the word "cat". Can you say "cat" with me?
But when "c" is followed by e, i, or y, it makes a soft sound, like the word "city". Can you say "city" with me?
So, a hard "c" is when it makes the sound like "cat" and a soft "c" is when it makes the sound like "city".
Make sense, little one?