Patch notes kind of vague about Amumu?

I feel kind of stupid about this but there are some parts of it I have questions about. What is Cursed Touch's duration, what is its cooldown? Unchanged? It seems like it has to be reapplied often from the looks of it.

Does the 15% bonus true damage apply to magic damage dealt by Amumu's first basic attack (for example if Amumu had a Wit's end or Lich bane for some reason) or does the auto attack apply Cursed Touch FIRST and then add bonus damage to any subsequent magic damage done?

Despair refreshes cursed touch, but does it apply it?

Why the need to specify on his ult that it only applies cursed touch after damage is dealt? Are they saying you need to auto attack your opponent to apply Cursed Touch before you ult if you want it to add bonus true damage? That just makes me grit my teeth.

Edit: I think I've mostly figured it out now, but my point stands that I felt like they were somewhat unclear about some things in the patch notes.