Need help/guide to set up my rdwc with neuts and ph

[Merkidge69]

Hey guys bew to hydroponics growing
Ive brought a 4 pot RDWC system and need a complete idiots guide on how to add the neauts and the ph up and down, here is the link to the one i got

Can i break this down into a 2 pot system?
How do i calculate the water volume in order add the neuts, as its recirculating do i add the pots together ans add the neuts in accordance to the total amount or do i include the header tank? I have no idea and need some sinplw help to add the neuts and maintain the system, thanks in advance.