What can I do if my iPad mini doesn't open after an update? When I push the start button, I can only see the Apple logo.

Hold down on the sleep and home buttons at the same time for about 10-20 seconds until the Apple logo appears on the screen then let go of the buttons.

Jac, first try what Demo recommended above as it solves a lot of problems. However if it does not resolve the issue in this case, follow the steps in this Apple article.

If your iPhone, iPad, or iPod touch doesn't respond or doesn't turn on - Apple Support

My pleasure Jac, glad that it worked... 🙂

check the battery ur ipad or iphone, before update need atleast 50%

try connect to itunes, then back up and update

THanks for the tip, but I have updated numerous iOS devices for myself, my family and friends and I have done OK on my own. 😉