The most important links are on
http://www.ghisler.ch/wiki/index.php/Total_Commander_for_Android
Beta version of Total Commander for Android can be downloaded from Google Play using a link
https://www.ghisler.com/betatc
Currently all Total Commander for Android public betas and stable releases at first go to Google Play, since it's the main distribution channel (stable versions then released on ghisler.com too). They currenlty are not announced on a forum.
Christian Ghisler's plugins stable versions are released on Google Play and ghisler.com, and still sometimes announced on a forum, but their beta announces (with changelogs) are usually Google Play-exclusive (although the apk files for plugins beta versions may be available for download on totalcommander.ch too).
As far as I understand, Christian Ghisler decided to focus on Google Play because it saves a lot of time needed to announce everything on ghisler.com and ghisler.ch (it matters because TC4A is a hobby project), and also the updates from Google Play come to its users autmatically (which also reduces the traffic for Christian Ghisler's own servers.)