Step from https://wiki.gentoo.org/wiki/Handbook:AMD64/Installation/Base I tried two times from start, step by step through documentation.
That is very strange. Please prepare a typescript with all commands you entered. Install also app-text/wgetpaste you will need it. Join the IRC channel #gentoo and we will help you there.
Unfortunately now I have no time to check this again. But I remember that did everything from documentation, step by step.
I have to close this ticket without detailed information. But we always ask users to report precisely about problems with the manual. So if there is a bug, hopefully another user will report it some day.