YouTube casting setting up

[#1]

As title I'm setting up a smart TV to cast from my smartphone but when I get a code from the TV my keyboard that comes up in the app is a numerical one so I can't enter the letters! How do I change it to qwerty keyboard? It's a Samsung Galaxy S6.

[#2]

Does this help, (pairing codes)

https://support.google.com/youtube/answer/3230451?co=GENIE.Platform%3DDesktop&hl=en

[#3]

@2u2me looks interesting the telly in question is being used by another member of the family at the moment so will try later thanks anyway