I have a few more doubts.

Question

Thank you.

The next morning (Can you say "on the next morning?)
We are being showed (is is a mistake or "shown" is correct?)
I waited for her to prepare/get ready (Are both possible?)

Answer 1

No, you wouldn't use "on" with "the next morning."

Use "shown" when it's the past participle (used as an adjective or with an auxiliary verb); use "showed" for simple past tense.

I wouldn't use "prepare" unless she was preparing SOMETHING (and that doesn't include herself!).