Defensive line when using a Libero

[jasonbuids]

I am using a Libero in my save with Man Utd at the moment. 
My formation is:
------------------ Poacher --- False Nine--------------

------------------------- Enganche ----------------

-------------------CM attack ---- CM support------

----CWB attack -------------------------------- CWB attack----

------------------------BPD-----------BPD-------------

------------------------Libero attack-------------

---------------------------------SW-------------------------

Actually, we are doing great with this tactic. The libero helps the team more balance in attacking pharse, he steps up and lets two CM go further and join the attack.
However, the defensive line still make me confuse. Is it the line between two CB? or is it at the position of the Libero? I am using a normal Denfensive Line right now.
Hope someone who uses this role before can give me an answer.

[Experienced Defender]

4 hours ago, jasonbuids said:

the defensive line still make me confuse. Is it the line between two CB? or is it at the position of the Libero?

D-line is where the CBs are, not the Libero.