You can't according to the blurb on the Club's website: Season Passes are no longer available to purchase online. Please contact us on 01226 211400 to order your 2015/2016 Season Pass now! I suspect if you were to try and ring that number it would invite you to ring back tomorrow morning when the office is open.
Go Here: https://www.eticketing.co.uk/barnsleyfc/ Click Login/Register If you have an online account associated with your season ticket, log in, otherwise click 'Activate my Account' Click on 'Buy Tickets' next to the everton match, and it should come up and say that you have a reserved seat, and you can click 'Add to basket' Then go to where it says 'basket' at the top, and checkout
I bought my Everton tickets online. I followed the link on the website to the e-ticket site, logged in, picked the Everton game and added the tickets to my basket. I have three season tickets in my account so I just repeated three times.
Just realised that when I log in the account number at the side of my name is different to that in my season ticket passbook. Have emailed the box office to sort it out - hopefully. Thanks for all your help.
If your using last season's log in details it will show that number. Try requesting a new Password, it worked for me