wy is this wrong
I will show you what you should do.
I will show you what you will have to do.
Why is "I'll show you what you need to do" wrong?
I suppose it's not wrong as such - rather a bit longer than required.
Do note that for such improvements it's best to use the 'meld een probleem'-button; e.g. see https://www.duolingo.com/comment/1386095 :)
The difference between "need to", "have to" and "must" is rather subtle in English I seem to remember. It is a subtlety we don't really have in Dutch. I think they all should be considered right. But you should just report it.
Jou laten zien means Let you see. You can let someone see something without showing them.
I will show you what you '' had " to do. Had = moet??