The properties panel is on the right side see fig 4
When you select a vertex in edit mode you will see which groups its assigned to and the current weight, 1 is max (equivalent to red in weight paint mode) and 0 is min (equivalent to blue in weight paint mode).
You’ll notice I have 4 vert’s selected see fig 1, the active vert is the one that you will see the weight of and how heavy it is. If all the verts selected are assigned to the same vertex group then you can just adjust the weight and hit the copy button to propagate the changes to the other selected verts.
If you find out that one or more verts you want to be included in the bones deform is not included in the vertex group, its easy to assign it. Make sure the vert(s) you want to assign to a group are selected and then select the vertex group that represents the deform bone and hit assign. see fig 2 and 3
In my opinion its a lot more easy to weight this way.
EDIT: just re-looked at your first post, for the beard follow the above instructions to see what other deform bone group its assigned to. I’m pretty sure its a weight issue. Even with a weight of 1 (red), if you have even the slightest amount of weight assigned to another bone, the deform will interpolate between those two bones.