As mentioned earlier, you can select from a number of manufacturers in several countries. One of the main considerations is if they make boards in the colors you want.

The colors for this project are blue (board), white (silkscreen) and copper/gold (bare metal). I could get this combination at JLCPCB.com. (Note: this is not an endorsement and there no consideration given / sponsorship / discount for using them).

Parameters

There are a wide variety of manufacturing choices available. The more obscure ones take additional time as they must gather enough board designs to make an entire panel. A PCB panel is a single board consisting of multiple individual boards. Once assembled, the panel is then broken apart, or depanelized, into the individual PCBs. 

FR-4 is the most common board type and the one described earlier. For simple boards, one layer may  be sufficient but two layer boards are more common and this guide's design uses both sides.

Choose the color for the board and silkscreen.

Two different finishes are available for exposed metal: HASL and ENIG.

HASL is when the board is dipped in liquid solder, making a silver finish. Lead & Lead-free (RoHS compliance) is usually available.

ENIG consists of an electroless nickel plating, covered with a thin layer of gold, which protects the nickel from oxidation. While a bit more expensive, it provides a pretty finish that will not oxidize readily.

The choices for this project are circled in green in the screen above. Note that this particular manufacturer has a minimum order of 5 boards.

Checks

The board house will look at your design to see if it is manufacturable according to their processes. Likely they will note any issues and bet back to you with issues and you should go into KiCad to make adjustments (like I did with the pointy pieces of the swish).

Now sit back and wait until your boards come.