Footprints of our ALMA and MUSE observations toward the MQN01 field. The orange and blue contours encircle the area where the combined mosaic PB response is ≥0.5 for ALMA band 3 and 6, respectively. Within these areas we performed the source search. Violet contour draws the MUSE footprint. The background is a composition of the JWST NIRCam F322W2 image (center and southeast corner) complemented with the VLT/FORS2 R-band observation (northeast, northwest, and southwest corners, and the southeast gap between the JWST NIRCam detectors). The point-spread-function-like emission of QSO CTS G18.01 has been subtracted in the JWST image revealing a nearby southeast quasar companion (Object B). Orange circles and blue squares indicate the locations of the ALMA CO(4–3) line-emitting and 1.2 mm continuum-selected sources in our ALMA band 3 and 6 observations, respectively. Green squares pin-point galaxy candidates detected in continuum at 3 mm in ALMA band 3. Gray hexagons denote sources corresponding to low-z counterparts, all but i5 show bright emission line in ALMA band 3. Violet crosses are the MUSE-selected LBGs belonging within ±1000 km s⁻¹ of the QSO CTS G18.01 systemic redshift. The dashed red circle shows the inner 100 pkpc around the estimated center of the protocluster core.