If you want to play Genshin Impact on PC, then unfortunately you won’t be able to pick it up on Steam, EGS, or any other launcher. Instead, you will need to download the game’s dedicated launcher from the official Genshin Impact website.
Click on the above link, and then click on the Windows option at the bottom right of the screen. This will automatically download the game’s launcher. Run the .exe when it has finished downloading and set your install folder to whatever directory you wish. It will default to the C drive, but this is just the launcher; the game’s installation is a separate option.
When the launcher has finished installing, it will automatically run, and you can click on the yellow Install button in the bottom right of the launcher. Set the folder you wish to install the game to while keeping in mind that it will eventually have a roughly 30 GB install size.
You will need to download 12 GB for now, and the length of time this takes will vary depending on your internet connection. Once that is complete, you can load into the game as long as you have a miYoHo account. If not, you can set this up at the Genshin Impact website linked above. In the top right corner of the website, you will see a Log In option, and clicking on that will allow you to set up an account if you do not already have one.
The game will be all set up and ready to go when it unlocks on September 28, although we suspect you will need to perform some form of download upon your first successful login when the servers go live.