SOS: Showing No Network in New Installaion

t am an endeavour-os user on mate-desktop. Just now I installed a fresh March-2003 EOS Cassini_Nova on a desktop machine. I installed the ‘Onlline’ install after booting from the live USB. Yad worked all right. I rebooted into the system and it is showing ‘No Connection Found’. And it is sharing another lan from the same router through which I connected the PC. During installation I made the connection ‘manual’ and assigned the IP with the router as 192.168.0,1. This laptop is connected the same way with the manual IP and it is working fine as I am reporting it.
And Dear Friends: I am in major calamity now: I have taken four days leave from the college to generate some material for my students. Already about fifteen hours are gone. I need the desktop immediately. Help my job and me. :upside_down_face:
Dipankar Das, Kolkata