Open Discord and go to your server
Click the server name at the top left
Select Server Settings
Click Roles
Click Create Role or select an existing role
Name the role Moderator
Set the permissions you want for the moderator role
Save the changes
Go to the member list or the server settings member management area
Select the person you want to make a moderator
Assign the Moderator role to that person
Make sure the role is placed above roles it should manage
Confirm the member has the correct permissions
Test the permissions if needed