Installing Valheim Plus on your Valheim Server
As of writing this article, installing Valheim Plus using our GCP (Game Control Panel) using the Unix Server Package requires contacting our support team through 
Discord or a Client Area Ticket. If your prefer, you can go through some of the process yourself, but we'll need to change the startup parameter for you. If you already have BepInEx installed, you can install Valheim Plus as a standard BepInEx plugin without Support intervention with these steps.
We're going to cover the steps for installing Valheim Plus manually and then hand off the startup command to the support team at the end while still providing the changes you'll need to make to it if you're not using our GCP.
We can do the entire installation process for you if you're using our Game Control Panel! There is no requirement for you to do any of the process on your own!
Installation
Valheim Plus provides a package with a version of BepInEx confirmed to work with that version of Valheim Plus, though it may not work with the latest version of Valheim so you might need to install a newer version of BepInEx separately and install Valheim Plus using the provided .dll BepInEx Plugin instead.
From the BepInEx Unix Package
After Downloading the UnixServer.zip file from the Valheim GitHub Releases page, you can decompress it on your PC and upload the files to your server's root directory using SFTP. This will install the version of BepInEx that was used to test and build this release of Valheim Plus, as well as the Valheim Plus BepInEx plugin. Starting the server from here is just like starting BepInEx, so you'll need to follow the same steps outlined for that in the Installing BepInEx article.
Once the transfer completes and you've followed the steps for startup, your can start your server to complete the installation of Valheim Plus and BepInEx, then move on to Configuring Valheim Plus and installing additional BepInEx plugins.
With the .dll
If an update to Valheim breaks the version of BepInEx shipped with the BepInEx & Valheim Plus Package, or you already have BepInEx installed, you can install BepInEx separately and load Valheim Plus as a BepInEx plugin. You'll need to start by installing BepInEx, if it isn't already. Once BepInEx is installed, you need to download the ValheimPlus.dll file from the Valheim GitHub Releases page and install it into your BepInEx plugins folder like you would any other BepInEx plugin. With the Valheim Plus plugin installed, you can move on to Configuring Valheim Plus and installing additional BepInEx plugins.
Configuring
Valheim Plus provides an extensive configuration file for every change it makes to Valheim. The extent of these configurations and changes are documented in their GitHub ReadMe file. Most configuration options are disabled by default, with the enabled ones mostly being integral to the function of Valheim Plus.
You can change the configuration options outlined in Valheim Plus' GitHub ReadMe by opening the configuration file, located at /BepInEx/config/valheim_plus.cfg, in the GCP's File Editor. Each configuration option is contained within a section that needs to be enabled as well, so to disable fog you'll need to locate and enable the Game section by changing the enabled value to true and then the disableFog value to true.
The headers on the GitHub ReadMe don't always match the section names, or where they're located in the configuration file and should be used more as a descriptor of what's available to change.
The Valheim Plus configuration file will be synced to clients with Valheim Plus installed when they join your server. It's highly recommended that your players also have Valheim Plus installed when they join your Valheim Plus server for this, and many other reasons.