The recent discovery at the Large Hadron Collider of a new particle consistent with the Higgs boson of the Standard Model is a major milestone for fundamental physics. One of the main priorities for the years to come is to study the exact nature of this new boson and in particular its couplings to Standard Model particles. The Hbb+ttH@LHC project has two main goals: establishing the observation of processes in which a Higgs boson is produced in association with a weak boson or with a pair of top quarks, and decays subsequently to a pair of bottom quarks; and studying the related Higgs couplings, in particular to the top quark to test the nature of the Higgs boson and probe new physics. A 4-year program was defined by a consortium gathering four teams to exploit the data collected between 2015 and 2018 by the ATLAS experiment at LHC. This run of LHC should quadruple the amount of data already collected, at an almost doubled centre-of-mass energy. The project is built on several techniques that will improve the sensitivity beyond the current state-of-the-art, notably: hadronic triggers to take advantage of fully hadronic decay channels as well as cope with the limitations of the lepton triggers at high-luminosity; jet-substructure techniques applied to high-momentum sub-channels; improvements to bottom and charm jet identification; use of color-flow and regression techniques to improve signal reconstruction. Those improvements will lead to measurements of physics backgrounds, observation and measurements of Higgs production in association with a weak boson and a pair of top quarks, and extraction of Higgs couplings.