Once the design phase of the Multi-Conjugated Adaptive Optics (MCAO) testbed for the European Solar Telescope (EST) is completed, the system has been assembled and integrated at the Instituto de Astrofísica de Canarias (IAC). The aim of this highly configurable optical testbed is to study different solar adaptive optics solutions, including Single Conjugated Adaptive Optics (SCAO), Ground Layer Adaptive Optics (GLAO), and MCAO. The testbed will be used to evaluate the performance of different wavefront sensing and correction strategies. It consists of different subsystems that are being integrated with high precision by using optomechanical elements mostly developed at IAC. The testbed emulates a 4-m telescope with a Field of View (FoV) of 70 arcseconds. It currently operates as a SCAO configuration consisting of: an illumination system with point-like and extended source capability coupled with a configurable turbulence simulator based on Phase Screens (PS); a pupil-conjugated Deformable Mirror (DM) with 820 actuators; a high order Shack-Hartmann Wavefront Sensor (SH-WFS) with 33 subapertures across the pupil, which measures on-axis aberrations with a FoV of 10 arcseconds; and the science detector. The next steps include the integration of the elements that will provide GLAO and MCAO capabilities, such as two SH-WFSs with a FoV of 70 arcseconds, and two DMs conjugated to different atmospheric layers. This contribution describes the optomechanical components designed and the alignment procedure carried out to set up each subsystem and configuration to be studied.