Adding gmail to my YT or Google account

i have yt or google account that uses hotmail that i use for yt but i dont have gmail so when the gmail icon i get this

(Add Gmail to your Google Account

By filling out this form, you are upgrading to Gmail, Google's email service. Gmail works on any device, blocks spam, and much more.

You will be able to sign in using your new Gmail address, which will become the primary email address associated with this account. We will send account updates, invitations, and other notifications to your Gmail address.

blablablahotmail. com will become an alternate email address for this account. You will still be able to sign in with it.

Alternatively, create a new Google Account with that email address and leave this one as is.)

have you guys done this and what happen will it just change hotmail. com to gmail?

thanks for the help.