How I can start Downloading?

I purchased 5 games.

gog.com/account, then select the game you want to download, and under "CLASSIC GAME INSTALLERS" click the game title. It should start downloading the installer file.

Alternatively you can download and use GOG Galaxy; if you're used to Steam that may be preferable.

I download Steam.. I cant find that phase where is that Classic Game Installers....

Are you using the GOG Goalaxy client or the website? The download procedures are a bit different for two.

Hover over your username at the top; when the drop-down menu appears, select "Games". When that loads (this page: https://www.gog.com/account), click on image of the game you want to download. A new menu area for that game will appear. Under the blue button that says "Try GOG Galaxy", you should see the text "Game Installer" or similar. Below this text, click on the name of the game.

I have
https://embed.gog.com/account
open and I have those 5 games available now.. and there is option INSTALL.. but It wont start open.. I try that Steam...

Are you using the GOG Galaxy client?

And why are you mentioning Steam? This is not Steam. GOG is a seperate store and has nothing to do with Steam.

There is no Steam here.

If you want to use the client, try here: https://www.gog.com/galaxy, Download, install, login.

Othewise download the setup files (see tfishell's screenshot) and simply run them. Like when you download other software (VLC, MPC-HC, AV.. you name it).

https://embed.gog.com/account is only for Galaxy client.
From a regular browser use https://www.gog.com/account like tfishell suggested.

OK.. It needed to restart the computer.. now it works. :)