HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

Nmesa, Download the full version from the website:
https://sites.google.com/site/heroes3hd/rus/download
Install it on top of your existing installation.
Make sure that the following 2 update servers are specified in the \_HD3_Data\Settings\#common.ini file:

Update.

- This recipe is universal and is recommended for use with any update issues.

I added these servers to the file, the mod updated (although it used to give an error), but the HoA tab does not apply, it gives an error.

Screenshot:
http://dl3.joxi.net/drive/2017/02/22/0018/1916/1234812/12/d166286bcb.jpg

Added 14 minutes later
or do I need to manually install some update for the game itself to HoA?

After installation, will it still be possible to play the regular complete version?