Questions & Answers about Kad izađeš iz škole, nazovi me.
Both kad and kada mean when.
- kad is the shorter, very common everyday form
- kada is a bit fuller and can sound slightly more formal or emphatic
So in this sentence, Kad izađeš iz škole, nazovi me. is completely natural. You could also say Kada izađeš iz škole, nazovi me. with essentially the same meaning.
Yes, izađeš looks like a present-tense form, but here it is used in a clause referring to the future.
It comes from the verb izaći = to go out / to come out / to leave.
Croatian often uses the present tense of a perfective verb after words like kad to talk about a future completed action:
- Kad dođeš, javi se. = When you arrive, let me know.
- Kad završiš, nazovi me. = When you finish, call me.
So kad izađeš means something like when you get out / once you leave.