There was no code for today’s game; you had to pay for it, leaving the space for the code blank as there wasn’t one.
Next Saturday, if you have a season ticket you should receive a code, so you should insert that instead of payment.
It’s either/or, not a combination of payment and promotional code. Next week it’s a code if you have a season ticket, or payment if you haven’t. Note the club’s advice about spam filters and e-mail addresses though.
It’s not free tomorrow owing to ‘EFL regulations’ – see note at the end of this link:
For league games you’ll be sent a link as a ST holder as long as the club has your e-mail address, as advised here:
https://www.scunthorpe-united.co.uk/news/2020/september/ifollow-iron-guide/
I’d advise contacting the club in advance on the e-mail address included on the link below; I did this today in order to both check that they had my correct e-mail address and to add the club to my ‘address book’ as advised here, getting a fairly prompt confirmation (though I wouldn’t necessarily expect that over the weekend):