Adding a page before the survey questions and adding sub-questions

Hi, I am very new to Qualtrics survey platform. I'd like to add a consent form page before the survey questions and a debriefing page after, before the participants leave the survey. I cannot find a how to manual anywhere.

I also would like to have sub-sub questions, so for one question, I would like to be able to ask more questions based on their answers before going to the next question (if you chose (a), then when was...., and it was on xxx date, then what was...). I can insert a group, but I cannot insert another group under a group.

Any help would be greatly appreciated.

Thanks,
Mitra