From Console:
Tutorial Video. Step by step below;
1
First Step
Login to your Wepwawet Control Panel

2
Second Step
Select your Server

3
Third Step
In the Console, Type whitelist [value]. If you’d like whitelist to be enabled, change [value] to on and if you’d like it disabled, change [value] to off.

4
Fourth Step
To add/remove a player from whitelist, In the Console type whitelist [add]/[remove] [username], Where [username] is the Game Tag of the player you want to whitelist.

There you go! You’ve enabled/disabled whitelist for your server and added/removed a player from the whitelist!