Xfinity Home Phone Service ... How would I connect an old fashioned corded phones, one in the bedroom and one in the kitchen?

Xfinity Home Phone Service ... How would I connect old-fashioned corded phones, they are not wireless phones. One is in the bedroom and one in the kitchen. I have an Xfinity modem in my bedroom next to a computer desk. I know I can plug my old-fashioned corded phone into the Xfinity modem by my computer desk that is in the bedroom, but how would I connect a similar old-fashioned corded phone in the kitchen which is nowhere near the modem that is in the bedroom? I do not have any active phone jacks in the house. One phone jack was installed in the kitchen when my place was built but then I found out that due to my area being rural, the local phone company does not provide landline service. So the jack in the kitchen was never active. Since I can't get landline service from a local phone company, I decided I want to get Xfinity Home Phone Service. But I am not technical and have no idea how I would connect the second phone in the kitchen.