Tools and Common Workflow

Kicad includes two other important tools:
"cvpcb" is used to associate footprints to components
This is a boring but necessary step in the design workflow
A well-written component already lists the few possible footprints
"gerbview" (or "gerbv", from the geda suite) can be used to verify your output
Never ship a gerber without looking carefully at it

So the standard workflow looks like this:
eeschema: you draw the schematic diagram and save the netlist
cvpcb: it reads the netlist, you associate footprints to components
pcbnew: it reads netlist and footprints, you route the PCB and plot gerber files
gerbv[iew]: you check the output
email/web: you ship the files and wait for the PCB to be delivered

Finally, mounting
You can buy components and turn on the soldering iron
Or, at extra cost, you can buy components, label, pack and ship for mounting
For this you need the BOM an position files, saved by pcbnew
Or, at even more cost, your manufacturer does everything for you
You must be most precise with your BOM file