A dynamic view of mass assembly is essential for understanding the formation of massive stars and clusters. However, interpreting evolutionary diagnostics from Galactic-wide surveys requires careful consideration of distance and environmental variations. The G316.8 filament provides an excellent controlled case: a 14-parsec, nearly linear structure comprising three contiguous subregions with comparable molecular gas reservoirs (each ~10000M_{sun}_), yet spanning a clear evolutionary sequence from a northern infrared dark cloud (young) through a central massive young stellar object (intermediate), to a southern HII region (evolved). The Linear filament and nested cluster evolution tomography (LANCET) project mapped the entire G316.8 filament with the Atacama Compact Array (ACA) at 1.3mm, achieving 6 arcsec (0.08pc) resolution over 26.7 arcmin^2^ (17.1pc^2^). By combining ACA 7m data with Herschel and APEX/ArT'eMiS observations, we produced high-resolution temperature and column-density maps. We quantified subregional differences using (i) dense-fragment statistics, (ii) column-density probability distribution functions (N-PDFs), and (iii) the scale-dependent structural diagnostic, the delta-variance. From young to intermediate to evolved, the maximum fragment mass increases from 8 to 160 to 490M_{sun}_, while the dense-gas mass fraction (>0.5g/cm^2^) rises from 0.4% to 2.3% to 9.6%. Along this sequence, the N-PDF develops a slightly flatter primary power-law tail and an additional, steeper secondary tail; the delta-variance slope becomes progressively shallower. Across G316.8, the subregional differences consistently indicate a coherent evolutionary trend of massive star formation, in which gas is continuously assembled into sub-parsec dense structures. The forthcoming 12m array observations are about to extend this dynamic picture by resolving dense core formation and probing gas kinematics and magnetic fields.