This is the 40th most frequent Swedish word.
första
"Första" in English means "first."
In this sentence, 'första' is used to describe the noun 'ögonkastet', meaning 'sight', indicating that it was the initial sight.
Det var kärlek vid första ögonkastet.
It was love at first sight.
In this context, 'första' emphasizes the order with respect to 'affären' or 'store', marking it as the initial one encountered.
Jag gick till första affären jag såg.
I went to the first store I saw.
Here, 'första' functions as an ordinal adjective modifying the noun 'personen', showing the sequence or order, i.e., the initial or number one individual.