Need help understanding how the watch-only internal wallet works to send funds

[v-wan]

Due to concerns of anyone being able to generate more than 20 invoices to cause a gap limit problem, I've decided to use the internal watch-only wallet for managing funds. That's great, but I don't understand what private key I need to input to sign the transaction when I need to send funds to my main wallet, as the only thing I got during the wallet setup was the seed phrase.

[v-wan]

Here are a few screenshots that I am confused about:

I decide to use the internal wallet, so I keep reading...

I click into the link and head into the page that describes the internal wallet

Cool, so now I see that the internal wallet is able to send funds

Looking at the screenshot of the Send page, I can see the destination address field where I will input the address of my main wallet, so that looks good, but to sign the transaction I need to create a new external wallet in BTCPayServer, when I just created an internal watch-only wallet?

Honestly confused

[pavlenex]

To sign enter the backup words.

[v-wan]

Ah cool, thanks!