# Freerouter Guidelines:

1. in pcbnew, using the Layers Setup dialog:
2. choose the number of layers, and enter the name of each layer.
These should look something like this:

- Layer[0] Back signal
- Layer[1] Power power
- Layer[2] V2_Signal signal
- Layer[3] H1_Signal signal
- Layer[4] Ground power
- Layer[15] Front signal

Notice that after the layer name there is a layer type field, either 'signal' or 'power'.
Any layer identified as 'power' will be removed from the layer menu in Freerouter, as this will be assumed to contain a power zone.
3. in pcbnew: establish board perimeter.
4. in pcbnew: load in the netlist so you have all the components defined and instantiated.
5. in pcbnew: establish any zones, inclusive of net association.
6. in pcbnew: do the degree of component placements you are comfortable with. It is a little easier to accurately position components in pcbnew than in freerouter, but either will work.
7. in pcbnew: set up the netclasses. Power traces might be a little thicker than signal traces. If so, add a netclass called 'power'. Make its traces thicker than what you establish for netclass 'Default'. Set trace width, spacing and vias for each netclass.
8. in pcbnew: export to DSN.
9. load up freerouter (keep it running for any subsequent iterations of 5) through 16) here).
10. in freerouter: load the project's *.dsn file. Immediately after a load, all components and traces (if any) will initially be 'fixed'. This is a 'lock in place' toggle that you can undo by selecting a region with your mouse and then selecting 'Unfix' from the menu. Occassionally you may want to re-fix a trace or a part, if only temporarily. This keeps it locked in place.
11. useful, not mandatory: in freerouter: set your move snap modulus, which seems to default to 1 internal unit. 20 mils in x and in y is about reasonable.
12. in freerouter: finish placing any components, you can change sides of a part here also, rotate, whatever.
13. in freerouter: route the board, and save frequently to a *.dsn file while routing in case of power loss. Pick the menu option for saving a full *.dsn file, not a session file (yet). The full freerouter *.dsn file is a superset format, one that can be reloaded in the event of a power loss. Whereas the *.ses file is not a complete design, but only with the *.brd file constitutes a full design. So it is important to backup your work to a *.dsn file while routing in case of power loss.
14. in freerouter: when done, or when you want to back import, then save as a session file, *.ses.
15. in pcbnew: backimport the session file
16. in pcbnew: at this point the zones have to be refilled. One way to do that is to simply run DRC.