LIBRARYFrom schematic to board: the layout workflow.

A finished schematic is half a design. The other half is the physical board, and the path between them is a fixed sequence: capture the schematic, give every part a footprint, push the netlist into the PCB editor, place the parts, route the copper, run the design-rule check, and export the fab files. Learn that sequence once and every board you draw follows it.

The two files share one netlist

A KiCad project holds two linked documents: the schematic and the PCB. You do not redraw one into the other by hand. They share a netlist, the machine-readable list of which pins connect to which. You draw the circuit once in the schematic, and Update PCB from Schematic carries that netlist into the board so the two can never silently disagree (KiCad).

A footprint for every symbol

Each schematic symbol is an abstract part. Before it can live on a board it needs a footprint, the real copper-and-hole pattern it solders to. Assigning footprints ties the symbol to a physical part and to its bill-of-materials line, so U2 on the schematic becomes one SOT-23-5 land pattern on the board. A symbol with no footprint cannot be placed.

The netlist is the contract

The netlist is what the PCB editor trusts. Every connection you drew, and only those, show up as a ratsnest: thin lines between the pads that still need copper. If a wire is missing on the schematic it is missing here too, so you fix the circuit in the schematic and re-import, never by drawing a stray trace on the board.

Then place, route, check, export

With the netlist imported you place the footprints, route copper to satisfy the ratsnest, run the design-rule check against your fabricator's limits, and plot the gerbers. Each of those is its own guide in this cluster. What matters first is the shape of the whole: schematic, netlist, placement, routing, DRC, fab files, in that order, every time.