1. Select Installation Location
   Determine where you want your Guild Wars 2 Steam installation to be located. The folder structure is something like this:
   
   C:\Program Files (x86)\Steam\steamapps\common
   Make sure there is there is no existing Guild Wars 2 folder within your Steam directory. If one exists, delete it to prevent any conflicts.
   
   
2. Open Command Prompt as Administrator
   Open the Windows start menu, type in "cmd" and select "Run as administrator" to ensure you have the necessary permissions for the upcoming steps.
   
   
   
   
   
3. Create a Directory Junction
   Use mklink to create a Directory Junction that points your Guild Wars 2 Steam folder to the standalone folder. The mklink syntax[learn.microsoft.com] for creating a Directory Junction is as follows:
   
   mklink /J <link> <target>
   Replace <link> with the path to your Steam Guild Wars 2 folder and <target> with the location of your existing Guild Wars 2 installation folder.
   
   For example:
   
   mklink /J "C:\Program Files (x86)\Steam\steamapps\common\Guild Wars 2" "C:\Your\Existing\Guild Wars 2\Folder"
   
   
   
   
   
4. Start Installation via Steam
   After setting up the Directory Junction, proceed to install Guild Wars 2 through Steam by clicking "Install" on the game's page.
   
   
   
   
   
5. Launch Guild Wars 2 via Steam
   Upon completion of the installation process, Steam will recognize the game as installed and immediately display it as playable in your library.
   
   

To utilize your ArenaNet account instead of your Steam account, follow these steps:

1. Access Guild Wars 2 Properties in Steam Library
   Right-click on Guild Wars 2 within your Steam Library and select "Properties."
   
   
   
   
   
2. Navigate to Launch Options
   Once in the Properties window, locate the "Launch Options" section.
   
   
3. Add Launch Parameter
   Within the Launch Options section, add the following launch parameter:
   
   -provider Portal
   
   

By using this parameter, Guild Wars 2 will utilize your ArenaNet account for authentication instead of your Steam account.

The popular open-source account managing tool Gw2Launcher (GitHub[github.com]) supports launching accounts through Steam.

The following Gw2Launcher settings are relevant to launching GW2 using Steam:

1. Access Settings
   Click on the menu icon located in the top-left corner of Gw2Launcher and select "Settings."
   
   
   
   
   
2. Navigate to Guild Wars 2 Steam Settings
   Within the Settings menu, navigate to the "Guild Wars 2" tab and then click on "Steam."
   
   
   
   
3. Adjust Steam Installation Location
   If your Steam installation is not in the default directory, specify its location here.
   
   
   
4. Configure Launch Behavior
   Choose how Gw2Launcher should behave when launching multiple accounts through Steam.

1. Edit Account Details
   Right-click on the account(s) you intend to launch via Steam within Gw2Launcher and select "Edit."
   
   
   
   
   
2. Access Launch Options
   In the account editing window, navigate to the "Launch options" section.
   
   
3. Set Provider to ArenaNet
   Ensure that "ArenaNet (Default)" is selected under the Provider dropdown menu.
   
   
4. Enable Steam Launch
   Check the box labeled "Launch through Steam" to enable launching via Steam for the selected account(s).

If Steam updates Guild Wars 2 without Gw2Launcher's awareness, launching the game may encounter issues. To resolve this, force-update the game by right-clicking on the affected account and selecting "update."

You've successfully configured Steam to utilize your standalone Guild Wars 2 installation. With this setup, your addons remain available, as the entire Guild Wars 2 directory has been seamlessly linked.