Ok so if you want “bp” to be attached to a specific socket of your skeletal mesh, here’s what you would need to do in your ACCharacter constructor:
For UE 4.7 and later:
bp->AttachRootComponentTo(GetMesh(), TheSocketName, EAttachLocation::SnapToTarget);
for previous versions:
bp->AttachRootComponentTo(Mesh, TheSocketName, EAttachLocation::SnapToTarget);
Is it what you are looking for ?