Crossing the Tang Dynasty Sign-In System

When the protagonist traveled through time, it was the eve of the Taiping Dynasty: there were undercurrents in the court, numerous clans, unstable borders, and the people were struggling to make ends meet. The protagonist starts out as a poor scholar at the bottom, relying on the "excess knowledge" gained from signing in, first improving farm tools, then forging iron and steel, then building bridges and paving roads, getting involved in weapons and people's livelihood - step by step, the "Datang" becomes what he drew.