So I'm having trouble understanding how ranking ladders work. i would like to use ranking ladders to have a staff team easily promote and demote a user.

Basically speaking, rank ladders are collections of groups for which the promote and demote commands are used. Each group in the rank ladder has a rank value, and PEX will promote or demote users up and down the ladder according to those values.

Since you're using PEX 2.x, you'd need @zml2008 to reply here if you need specific commands or have other more specific questions.

Thank you, I'm almost certain i figured it out completely.

You're welcome. If you're satisfied, you can close the ticket if you want.

Another question is how would i set any new user to default ?

Using the command /pex default user parent add group <default group name>