It's written on the first post. But I'll copy and paste to make it ever more simple.
https://www.thebuddyforum.com/demonbuddy-forum/plugins/235899-plugin-autofollow-1-0-10-a.html
Instructions
Basic Setup
Start Multiple D3 clients in windowed mode (add -launch to target of a Diablo3.exe shortcut).
Start as many DB instances and login (protip: click the refresh button to update dropdown to valid D3 clients)
So now you should be in the hero select screen out of game on all bots with DB connected to each.
For all followers load the profile \db\plugins\FollowerCombat.xml
For the leader load any normal profile.
Click start on DB for the leader and then start all the followers.
Manual Leader Setup
Do the same as basic setup, except for leader bot load the profile \db\plugins\LeaderManual.xml