What guitar plucking is.

1. In order to pluck bass guitar strings, use the index (#1) and
middle finger (#2) while resting the thumb on a pick guard
or pickup.
You should use at least two fingers.
When using two fingers it is very important to alternate the
fingers. 1-2-1-2-1-2.
Practice slowly and make sure they are alternating as if
they were going for a walk.