The player manager is an easy way to manage your players (as the name suggests) and there are a ton of features that it includes. This forum will go over how to find the player manager and what its uses are.
Finding the Player Manager:
To start finding the Player Manager, head to the console of your server, it should look something like this:

Then on the sidebar, look for the 'More' button:

Click on the 'More' button a side menu will pop up, you will want to click on the 'Players' option:

And boom! You are in the Player Manager:

Now for its features:
At the top of your screen there will be a list that looks something like this:

We are going to go over these sections and what they mean:
Operators:

Whitelist:

Banned Players/IPs:

Offline Players:

If any of your players are online, they will show at the top of the screen like this:

Now lets click on a player name and see what happens, if you look back at the player manager screen, if players have played on your server before or have been recognised by your server, their username will appear in one of the tabs. By left clicking we get a lovely menu:

This is the Actions Menu, this allows us to do actions more efficiently than just putting a command into the console. On the Actions Menu we see the following features:
- Username
- Online/Offline Status
- Player Skin Model
- Player's UUID
- 8 Quick action buttons:
- (Un)Whitelist
- (Revoke)OP
- (Un)Ban
- Wipe Player
- Kick Player
- Clear Inventory
- (Un)Ban IP
- Kill player
Some actions can only be done when the player is online on the server, such as:
- Kick Player
- Clear Inventory
- (Un)Ban IP
- Kill Player
When doing certain actions you will get pop-ups that confirm your reason and ask for an input (for example a reason for banning a player):
Now that we have covered the features of the Actions Menu, if you look at the bottom right of the Actions Menu, you will see some fancy buttons that look like this:

If we press on stats we will get this menu:

This is the Stats Menu; this is where we will view the available player stats such as:
- Last coords the server logged (Mainly logs when they have tped, log in/out etc..)
- Gamemode (Survival, Creative, Adventure, Spectator)
- Playtime (How long the player has spent on your server)
- Kills (How many players the player has killed)
- Deaths (How many times the player has died)
- Level (How many XP level the player has)
- Last Death (How long ago it was since the player last died)
On each of the sections of the player manager (Opped, Whitelist, Banned, Offline) it lists any players that fit into that category, here is what that looks like:

See that plus icon? Thats where we can search for any player we want and add them to that list, this is what each "Add a player" pop-up looks like for each section (except offline):