This project is a lot more free-form than other projects, as you've got to set it up to connect to your own home blinds.
The stepper motor can be tricky to debug, so connect it up first and make sure that it operates normally.
looking directly at your stepper motor, you can see the 4 wires going left to right, what you want to do is connect them to MOTORA and MOTORB ( + and - ) for both, with the outside ones connecting directly and the inside ones crossed over.
Use the File->Examples->AccelStepper->Bounce should provide an easy way to test and make sure that it works correctly. Best case if you wire it wrong, is that it will spin the opposite way. If it doesn't spin at all, is weak, or just sits and vibrates, then you've got something wrong with the wiring, so double check the connections.
Find a way to mount the IR receiver away from sunlight and so you can point the remote right to it. Thankfully due to the XC3718_codes.h file, it will not decode and try to run a faulty signal if it gets an interrupted source of IR such as from bouncing off the wall or etc.
These should be fairly obvious where to mount. RGB status LED is to indicate to you what it is doing, so you can have it fairly front-facing, or even try to diffuse the brightness with a panel or something so you can get a dulled status bulb.
The solar panel should be in direct sunlight, and will need to have leads soldered to it.
Connection to blinds is probably the most difficult and "creative" part of this, as you've got to find a way to interface and everyone's set up is a little different. (if you manage to finish the project and connect it to your blinds, send us a picture to github@jaycar.com.au so we can show it off!)
Here's a few ideas to get you started:
 mechanism is often used in boats:
Using a large diameter barrel, you can wound a string around so that both ends of the string are coming out of the barrel, then when the barrel turns, it will pull on one side while giving slack to the other. This is perfect for tying string to the blinds if you do not want to deconstruct the mechanism on your blinds already.
You can use a hub to attach to the spindle of the stepper motor, and interface between either the Windlass barrel above, or connect to the spindle of the base of the rotary system, depending on what your set up is.
It's possible to mount the stepper motor ABOVE the blinds, and interface to the spindle shown in the picture above, through either a belt-drive or direct attachment
Another location to place it, placing a bottle-cap or gear set to the plastic mounting so it can move the bead-lead. My blinds at home actually have a rotary attachment, so a great idea would be to mount the hub YG2784 straight to it.
Windlass idea. this is a great way to have non-destructive attachment to your blinds system, as it adds another element which can act as a failsafe.