The core skeleton is a piperazine ring (a saturated six-membered heterocycle with two nitrogens in opposite positions). Each nitrogen carries a distinct substituent:

1. On N1: an acyl group, where a carbonyl carbon (C=O) is directly attached to the nitrogen.
    - This carbonyl carbon is also bonded to an indole ring (a fused bicyclic system composed of a benzene ring and a pyrrole ring, with the pyrrole nitrogen adjacent to the two ring junctions).
    - Specifically, the carbonyl carbon links to a benzene carbon of the indole that is meta to the junctions; of the two such carbons, the one chosen is the carbon further to the pyrrole nitrogen.

2. On N4: a tertiary carbon substituent, which is bonded to:
    - a hydrogen atom,
    - a methyl group (-CH3), and
    - a 3-fluorophenyl ring, in which the carbon attachment point is on the benzene ring and the fluorine atom occupies the meta position relative to this attachment.