Installation and Configuration Guides for Proxmox Backup Server
Initial Setup Guides for Proxmox Backup Server

Installing Proxmox Backup Server
This article goes over steps for installing Proxmox Backup Server. There is multiple options on where to run PBS instance, however for best performance running it on seperate bare metal machine would be the best option. PBS can run in virtual machine if needed, just like any other OS with ISO image. If PBS runs in vm do not select that vm when scheduling backup job with PBS.
Prerequisite is machine ready and Proxmox Backup Server ISO flashed to flash drive
Installing PBS
Boot the machine and select flash drive with ISO image
Install PBS with a graphical user interface
Accept EULA
Select Target Disk to where OS will live (Hopefully separate from main storage if you have couple)
Fill in your country, timezone and keyboard layout
Choose a unique password and fill in your email address for your root access (you can disable root later)
Fill in your network details
ID: A name for the connection, e.g., pbs-backup
Managment Interface: unless you want/have a different interface, leave this as default
Hostname: "NameOfYourPBS":local
IP Address: Choose a static IP address
Gateway: Fill in the gateway
DNS server: Fill in a DNS server
Finish the installation by clicking continue
Access the PBS Dashboard by going to its [IP Address] and pot 8007 eg. https://192.168.1.101:8007

Configuring Updates for Proxmox Backup Server
This article goes over setting up Community based updates. By default, PBS (and Proxmox VE), are configured to download the 'Enterprise' repository for your updates. Unless you do have an enterprise license, we need to add the 'no-subscription' repository and disable the enterprise repository.
 
Login to PBS
Go to Administration, Repositories and click Add
Select the 'no-subscription' repository and click Add
Select the 'pbs-enterprise' repository and click 'disable'
Go to 'administration', 'Updates', and click 'refresh'. This will will check the repository for updates. Afterwards click on 'update' or run update from the ssh or shell
sudo apt update && sudo apt upgrade -y

Configuring Datastore
Datastore is where the backups will be saved. This article goes over configuring datastore using a disk on the machine. If not using volume from machine check out this article to use NAS storage via NFS
 
Creating Datastore
Login to PBS
Under Storage/Disks got to Directory
Click Create: Directory
Select the disk
Choose Filesystem (I chose ext4)
Give datastore a name
Make sure Add as Datastore is selected
Click Create
Setting up Datastore in Proxmox Backup Server
Under Datastore click Create Datastore
Name: Choose name to call it
Backup Path: Select the path to folder directory on the machine. 
Under Prune option this is personal preference, but deduplication really lowers the amount of space needed, so keeping more backups is not bad decision.
Once done click Add
When the datastore is added, clicking on datastore will give you info, and also ability to adjust Prune and CG Jobs. Also, under Verify Jobs it's good idea to add Verify Job for checking that backup isn't corrupted and that will work when needed.
Under Prune & CG Jobs make sure CG Job is set to daily. You can adjust Prune job here as well
Under Verify Job click Add and schedule Verify to run Daily and Re-Verify to run every 30 days
It is optional to create a namespace. Storing your backups in separate namespaces is very useful if you ever plan on planning to use your PBS to store backups from multiple Proxmox hosts, or even other Linux server.
Under Content click Add Namespace
Parent Namespace: This would be folder in which this subfolder will live, usually root
Namespace Name: name of the folder where backups will live

Security Configuration
It is optional but recommended to create a separate backup user. In the next step we will connect our PBS to Proxmox VE, and for that you need a user. You could simply use the root user, but best practices dictate that a separate user is better for security reasons. Also, Add Two Factor Authentication to secure your root account.
Note: a user that has Two Factor Authentication, can't be used to connect your PBS to Proxmox VE. That is also why we created a separate backup user in the previous step.
 
Adding Backup User
 
Login to PBS
Under Configuration go to Access Control and click Add
In new user window
Give it a name
Realm: Proxmox Backup authenticator
Choose strong password
Make sure Enabled is checked and it doesn't expire
Now that the account has been created, we also need to give it the correct permissions.
Go the Permissions tab
Click Add and select User Permission
In User Premission Window
Path: select datastore only
User: choose backup user you created
Role: Choose DatastoreAdmin
Make sure Propagate is selected
Click Add
 
Enabling Two Factor Authentication
 
Go to Access Control
Select Two Factor Authentication and click Add
Select TOTP and Fill the required details using your preferred password manager
You have to do this for each user