Sending examination certificates in pdf.

I have received an unconditional offer from Northumbria University. However, they are asking me to send my qualification certificates in the form of pdf using the ‘Applicant Portal’. Will the university email me the details on how to access their portal or do I have to find it on their website? I’ve looked on their website and I haven’t found any ‘applicant portal’ that I can send my qualifications in. I have a month to respond to the university after I have decided to accept their offer. I have also checked UCAS track, and a letter there says to basically do what I have explained. Please help me out ☹