The High Luminosity LHC (HL-LHC) Project is an upgrade program of the Large Hadron Collider (LHC) at CERN, focused on increasing the luminosity, thus significantly enhancing the potential to discover new physics from rare events. Among many activities ongoing in this framework, the implementation of novel superconducting radio frequency (SRF) cavities - especially Crab Cavities - is foreseen for compensation of the bunch crossing angle, which is a reducing factor for LHC luminosity. Two different crab cavity designs have been developed: the Double Quarter Wave (DQW) and the Radio Frequency Dipole (RFD). A prototype cryomodule, hosting two DQW cavities, has been fabricated and assembled3 for validation tests, which are currently ongoing in the Super Proton Synchrotron (SPS) at CERN. Since 2016 the engineering team from IFJ PAN has been contributing to the Crab Cavities & RF project (Work Package 4 of the HL-LHC Project). This contribution has included the following activities: mechanical, electrical and vacuum preparation of DQW crab cavities for cold tests in the vertical cryostat, as well as the assembly process of the fully-dressed DQW cavities. After successful RF cavities qualification, the assembly of the DQW cryomodule and its preparation for the tests was also performed with the participation of the IFJ PAN team.