In ultrarelativistic heavy-ion collisions at RHIC energies, charm quarks are predominantly produced in initial hard partonic scatterings. Therefore, they experience the entire evolution of the hot and dense medium produced in these collisions, known as the Quark-Gluon Plasma (QGP). The STAR experiment is capable of studying the production of charm quarks and their interactions with the QGP through the reconstruction of the hadronic decays of D$^0$, D$^\pm$, D$^\pm_\textrm{s}$ and $\Lambda^\pm_\textrm{c}$ hadrons. These measurements are possible thanks to the excellent track pointing resolution of the Heavy Flavor Tracker (HFT). In these proceedings, we present recent results on open-charm hadron measurements in Au+Au collisions at $\sqrt{s_\textrm{NN}}=200$ GeV. In particular, we discuss the nuclear modification factors of D$^\pm$ and D$^0$ mesons, which provide insights into the energy loss mechanism of charm quarks in the QGP, and the D$^0$ elliptic and triangular flow coefficients, that probe the charm quark transport in the QGP. We also present the D$^\pm_\textrm{s}$/D$^0$ and $\Lambda^\pm_\textrm{c}$/D$^0$ yield ratios as a function of transverse momentum and collision centrality that help us better understand the charm quark hadronization process in heavy-ion collisions. Finally, we show the rapidity-odd directed flow of D$^0$ mesons, which is sensitive to the initial tilt of the QGP bulk and can also probe the effects of the initial magnetic field in heavy-ion collisions.