I started playing with Linux in the late 90s while I was in grad school. Slackware 3.x. I think I might have tried one or two others, but since I was somewhat familiar with Unix, Slackware was the easiest for me to learn.
I got them via CD ROMs; I’m pretty sure they came with a book on Linux (I think it included several distributions on CDs). I don’t think I have that book any more; I likely got rid of it long ago as it was badly out of date. But my memory is that it was published by Que, a publisher that I had good experience with on other topics. (dBase III, for example) I’m pretty sure it was this one…leave it to Amazon to still have it.
I recall recompiling kernel because it was “so much faster” (I cringe at myself now for thinking that - it probably wasn’t even true on my Pentium 133 machines). I also remember spending time trying to get X-windows configured, but I was successful. I think I was using fvwm95 window manager, a Windows-like experience. I started using Linux essentially full time pretty quickly.
A few times I got frustrated with Linux and tried to switch back to Windows, but the headaches of Windows always quickly drove me back to Linux. Linux is not perfect, but Windows is even worse.