On Windows, you do need some effort if you have no idea what is going on, but it isn't like those systems were sloppily put together, there are some design ideas and you get used to them... eventually. But once you do, things more or less fall into place.
A biggest issue with working on older Windows APIs is that modern web-based MSDN documentation is simply awful and the best you can do is to find old MSDN CDs/DVDs that often contained more information than the site (especially articles), better organization and -especially- much faster interface (being local and all, but also the cdroms around late 90s / early 2000s were in CHM format are lightweight). And 99.999% of the documentation you'll find on these CDs will have the same text as the documentation (if it still there) on MSDN (and very often the same text that is on the much older WinHelp WIN32SDK.HLP files too).
Like most things Microsoft on desktop, everything went downhill since .NET people took over and decided to redo things their way (yes, .NET brought some nice things too, but it created an internal schism - before .NET became a thing, desktop tech in Windows was mostly coherent) and now history is repeated with UWP.
A biggest issue with working on older Windows APIs is that modern web-based MSDN documentation is simply awful and the best you can do is to find old MSDN CDs/DVDs that often contained more information than the site (especially articles), better organization and -especially- much faster interface (being local and all, but also the cdroms around late 90s / early 2000s were in CHM format are lightweight). And 99.999% of the documentation you'll find on these CDs will have the same text as the documentation (if it still there) on MSDN (and very often the same text that is on the much older WinHelp WIN32SDK.HLP files too).
Like most things Microsoft on desktop, everything went downhill since .NET people took over and decided to redo things their way (yes, .NET brought some nice things too, but it created an internal schism - before .NET became a thing, desktop tech in Windows was mostly coherent) and now history is repeated with UWP.