The order page opens and the eSIM is issued onto it, usually within about a minute. The page updates itself while it waits.
On it you get three ways to install: a one-tap link for a recent iPhone, a QR code, and the two values to type in by hand. Any one of them is enough.
If you gave an email address, the same details arrive there too. If you did not, keep the order number from this page.