Hi, all. Hope you guys are doing great.

Without further ado, I have 4 different/not related questions:

1) What exactly does it mean to let a note ring? Does it mean to let the note go on without stopping it? As in sustain it?

2) What's the technique for the following tab? Inside the circle.

This is a bit of a hassle. I can't exactly get my head around how to get the G string ring along with the B string when you bend the 12th fret. Do you I have to fret them both with my pinkie? Or should I only fret the B string but strum both? Because when I fret only the B string, the moment I reach the G string with my finger it mutes it.

4) Generally speaking, what does it mean in the tab when a note is in between brackets?

As always, thank you so much for all your help in advance. :)

Have a great one. :)