This document is a draft Request for Proposals (RFP) for the construction of the Near Detector Complex as part of the Fermilab LBNF NSCF project. The RFP describes the required construction services, which include a service building, primary and secondary shafts, detector cavern, and site improvements. The work is to be awarded as a Firm Fixed Price (FFP) subcontract. A mandatory pre-proposal conference is scheduled for July 10, 2024, and all prospective offerors must attend to be eligible for award. Offeror questions are due by August 8, 2024, and the proposals will be valid for 7 months from the proposal due date. The Fermi National Accelerator Laboratory, which is part of the Department of Energy, is the federal agency issuing this solicitation.