Please help a newbie father trying to understand dashboard version

The site I was “picked” to make for my daughter’s gymnastics team appears to have been hacked. Every time you try it on a mobile device of any sort (apple or android) you get redirected to some bad places.

I have been doing some searches on how to stop it but I use the dashboard version of WordPress.org to create the site. I am completely new to this and was lucky to even get the site going. I stopped all the plug-in’s and changed the password but it is still hacked.

I tried to understand the ways to resolve it but it appears that most people use a downloadable version of wordpress to create their sites.

My questions are:
1. Should I use the downloadable version? If so how hard is it to load?
2. What can I do in the meantime to stop this redirect on mobile devices?

Again, I have never coded in my life, I am just a father of a gymnast who is trying to help a non-profit.