Ok you create a account here https://activism.openworlds.info/about this will put you into a small actavists community that is connected to over a million mostly normal and some weard people spread over thousands of servers. You can now fallow and talk to anyone on the network and they can fallow you.
This will give you a good desktop ui
For mobile https://tusky.app/ install this and add the account you setup on activism.openworlds.info to get a good mobile expirence.
Dont know best apple apps but the are a few
Next stage you need to find 20 or more people to fallow. You can do this by useing the search and hashtags. And/Or the are some lists here https://communitywiki.org/trunk of intresting people. Remember you need to fallow 20 or more people for the system to start to work
Then post a intro, use hashtags etc.
Make the effort to talk to people on the network you will likely not know any of them so its like going to a strangers party. But its a fab party when you warm up and build some connections.
Keep posting each day, comment on others posts. The social flow after a while will become self sustaining. Keep your failbook account active at the same time, start to offer a helping hand to your #dotcons friends to take the step, then spend the time introducing them to your #openweb network.
You have stepped away to the openweb.