I tried reusing my old MacBook Air late 2010 (MacBookAir3,1) as it got quite slow running on MacOS X.
Famous distribution will be good options to avoid so many manual configuration. Ubuntu must be a viable candidate but Unity is heavy for the old Mac. Obviously light flavours are preferable. I chose Ubuntu Studio, which adopt Xfce and has various pre-installed apps. The version at the moment this article was written was 18.10.
Installation of OS can be done without specific consideration, however, we should fix some issues and make improvement for some topics below.
Individual topics are covered in the next articles.