Trying to connect Thermostat to Google Home App

[Craze27]

My son installed my Receiver for me & did some set ups on the actual Thermostat when I was at work (so obviously I had my phone)  got home & started trying to add my Nest Learning thermostat to my Google Home App & I get as far as entering the 6 digit pass code from my actual Thermostat then the next page it says 'Choose the last four digits from the serial number ' I understand where the serial number is but I cannot physically add them on my phone as where ever I touch my phone my keyboard does not come up to type anything in. I have a Samsung S20+ phone.  I have tried watching Videos & tried looking up on Google.  It says about a "Entry Key' which I did get from the thermostat but nowhere to put it on my Google Home App. Please be aware I have several devices already set up on this App so know how to add devices & obviously have an account. 

[MplsCustomer]

@Craze27 

We do not have a Nest thermostat, but the Nest Learning Thermostat and Nest Thermostat E get installed in the Google Nest app (and once installed should then appear automatically in the Google Home app provided that you're logging into both apps with the same Google Account), while the Nest Thermostat gets installed in the Google Home app. Google Nest does not specify this very clearly:

https://support.google.com/googlenest/answer/9274936

(I don't know what "setup" your son performed, or whether he installed the thermostat in his Google Nest app on his Google Account, which would complicate the situation.)

If you do get your Nest Learning Thermostat installed in the Google Nest app and it does NOT appear in the Google Home app, I've seen numerous posts from other customers where this has happened, and many of them used this workaround to correct the problem:

1) In the Google Nest app, create a new, temporary Google Nest "home/structure".

2) Go to that new, empty Google Nest "home/structure" in the Google Home app and delete it.

This apparently forces the 2 apps to sync and the thermostat then appears in the Google Home app.