First, excuse my english but I'm french and my english is a little rusty

I have a smartphone (Asus ZenFone 2) with
- Android 5.0 (Lollipop)
- FireFox 51.0 (updated today)
- AdBlock Plus 2.8.2
I would like to add or configure personal filters, but I can't. When I go to tools > plugins (of FireFox)> AdBlock Plus 2.8.2, I can just :
- Disable (AdBlock Plus)
- Uninstall (AdBlock Plus)
On my computer, I can do it easily, but I can't do it on my smartphone.
Could you please help me and explain to me how to add personal filters ?
Thank you for your answers.
Have a nice day.