The netlist file (.net) is the file responsible to communicate between eeschema and pcb_new.
To do this communication you export the netlist in eeschema (tools->generate netlist file)
Then you open pcb new (either from the main window or from the toolbar in eeschema).
In pcb new you then import the netlist (tools->netlist)
Thank you so much for your reply. But…
Now I see that I don’t have associations between intems on the schema and footprints. For example, how to find footprint exactly matched to LM358?
In the libraries attached to KiCAD I can’t find any matching item.
Well what LM358 exactly? That part comes in many different packages. (TI for example sells it in TO-92, TO-CAN, SOIC-8 and LCCC-20 packages.)
The official library is build upon the idea that many different symbols can share the same footprint. (This makes maintenance a lot easier.)
Lets assume you have the TO-92 or SOIC-8 version in mind then you might find symbols in the lib that are already connected to the correct default footprint. (Depending on the library version you have installed)
If you don’t find that symbol or you have a different package, then you need to make a symbol with the correct pin numbers and connect it to the footprint. (All but the lccc footprint should be in the lib.)