In regards to installation there is a way for the handy person to install wall splits. (now some people may not appreciate me saying this but seeing as though i am from the other side of the world i don't really care). But it is known as air purging.
Now this is not how me or a professional would do it these days as we would use a vacuum pump but it can be done and i know of a lot of old school HVAC guys who still on the right occasions use the air purge method.
Also taking into account it could save you the head aches you mention it might be worth a shot.
Anyway in short if you have access to a couple of specialist tool's it can be done, mainly this tool is known as a flaring block search google for it and you will see a couple of different types. You will also need a deburring tool, a file can be used if done correctly.
You will also need the correct size annealed copper line generally for that size unit it would be 1/4 inch and 3/8 or maybe 1/2 these will need to be insulated also.
As for the connections the brass nuts come with the ac simply undo them and slide them over the prepared pipe.
Tube Preparation (This is important to producing a good flare, also do not let any dirt water dust copper filings nothing get into the pipe. keep them clean.
For a good flare, the end of the tubing must be cut square and free of burrs. The tool of choice is a tubing cutter. Good tubing cutters have strong, sharp cutting wheels opposite a smooth pair of rollers that hold the tube firmly as it turns. The tube must then be reamed out to its original diameter. Most tubing cutters have an attached reamer, but a more effective one with multiple sharp blades can be purchased separately.
Now here is a link to a video on how to flare annealed copper pipe,
Also a small word of warning these flares must be perfect due to the high pressures of R410A otherwise it will leak out and your ac wont work then you will need an ac guy to come and charge it back up with refrigerant.
So what they should look like is this all shinny no imperfections, it may take a couple of goes to get it right but be sure to get them like this
If they do not look like this then your tube preparation needs to change cause your doing something wrong.
Once you have them done connect it all up make sure the lines are insulated and you are ready to air purge this is very simple. Now on the AC outside where you connected the copper lines onto the unit undo all the caps the larger connection should have two the smaller connection only one (but maybe two) now on the larger connection there will be a valve like in a bike tube this needs to be pushed in with a screw driver, at the same time take your Allen key and open the valve on the smaller connection. You should now be hearing the air being pushed out keep doing this for about 15 seconds or so.
Lastly connect up the wiring should be all labeled 1 to 1, 2 to 2 and so on there will also be a spot that should say L and N this is where your power supply comes in (that is if it does not have a plug to plug into a power point)
Lastly and MOST importantly make sure you connect the earth wires to both outside and inside units.
Hope that did not confuse you otherwise u need a pro to do it. worst cause scenario you mount the indoor unit and outdoor unit then the HVAC guy can just connect it up not really needing to look inside (if you do the wiring that is)
