I have this mesh and armature found in this blend file. What I want to do is to connect the bones with the created vertex groups. And I don't want to use automatic weighting option as this will create different and new vertex groups. I want to use the vertex groups I manually created in the attached blend file. Please if anyone could please advise.
Rename the vertex groups so they have the same name as the bone you want to deform them. Add the armature modifier. Make sure "Vertex Groups" is checked (it is by default) and you are done.
I'm sure there's a better way (and I usually create the groups after parenting) is to parent the bones with automatic weights, then go into edit mode, select a vertex groups vertices, then go to the corresponding bone and assign those vertices (removing any that were in the bone group previously). Or you could remove the automatic bone groups and rename your own vertex groups Bone, Bone.001, Bone.002, and so on. Or, you could parent the bones with empty groups and then copy from one group to another.
I'm sure there's a setting, however, in the mess of buttons and sliders that changes the bone groups.