This question makes no sense at all. Please try again.
"I get a 4% APY for 6 months."
This is insufficient. You MUST specify the compounding methodology. Simple, compound, days, months, and on and on...
"With how much money do I end up when starting off with 5 000 $ after 6 months?"
Ambiguous. Is the $5000 at the beginning of the 6 months or at the end of the six months?