NICA Booster: a new-generation superconducting synchrotron

In November +/- December 2020 and in September 2021, the first two beam runs of the Booster Synchrotron a new cyclic accelerator of the NICA (Nuclotron-based Ion Collider fAcility) complex were performed at the Laboratory for High Energy Physics, Joint Institute for Nuclear Research. New technologies (previously not used in Russia) were developed for the Booster's construction based on new physical and technological solutions. We describe these technologies and solutions and also the methods used in constructing and testing the accelerator systems. We present the results of the first two runs.