Schematic in EAGLE
Started by downloading EAGLE, using its free non-commercial version.
Eagle is divided into two parts: the Schematic and Routing. In the schematic interface, the placement of the components is unimportant, but rather the connection between each component and the micro-controller. Schametic is where you just through the components in. Had some bugs while renaming the pins, didn't always "find" other pins on the canvas that had the same name.
Typing "ADD" enables to pick components from a list. The problem is ofcourse knowing which components and sub-components to use. Many of them are actualy the same size (resistors that bear different names and functions), but as long as they are the same suze, it doesn't realy matter.

ATtiny44
Trying to figure out the pins in ATtiny micro-controller.

Routing
Routing was guess and miss of moving and rotating components.
Tried using the "AUTO" command to automatically find the paths between components, but this suggested 2 layers for most layouts of components.
The AUTO mode has options to 1.automatically choose the right grid for the routing, and 2. to use a double-layer, or not.
It also gives an option to choose the effort of finding route, that changes the positions of components.

Grid and Routing under the micro-controller
The default grid is 0.05 inch, which is failry wide and may prevent from using 2-3 lanes of route, when needed to squiz-in. Changing the GRID to smaller gaps may couse covergance of routing.
The end mill is programed to 0.014, so what I gather is that 0.025 should be the minimum, before causing shorts.
The routing underneath the micro-controller is essential to connect components without bridging, but later in the soldering part, found-out that it is hard to solder the pin to a route going the other way.

Exporting
Exported at 500 dpi, monochrome

Doubling dpi if its a Retina screan, which I have...
The first board I milled turned out X2 in size.
Turns out that when the computer is Retina screen it's actually double in size relative to the mod. So instead of 500dpi, I put 1000dip.

Routing and Soldering underneath component
Again, it is a bit of challenge to solder underneath the component, since the solder is mostly on the front of the pin, where there is no actual contact with the pin.

Soldering