How to redirect users from site A to site B with minimal losses?

Question

Blogs

There is a site on the blog.aaa.ru domain. It has been running for several years, it has regular visitors, feed subscribers and is well indexed by search engines.
I have a bbb.ru domain, to which I want to transfer visitors to the site blog.aaa.ru, with the least losses. The content on bbb.ru is identical to blog.aaa.ru. This is, in fact, one site, just under a different domain name.
What is the best way to do this, with minimal loss of position in search engines, visitors coming from their bookmarks, and so on?

Answer 1

1. Make the same robots.txt on both domains with the directive for Yandex Host: https://bbb.ru (it is possible without a protocol, if it does not change)
2. In the Yandex.Webmaster account for the old domain, in the Indexing -> Move site section, select
the domain to which you are moving (both domains must be in your Yandex.Webmaster account with verified rights, indicate that you are moving to https if necessary) being processed (this may take some time).
4. When there is a message in Ya.Webmaster that the site has been successfully moved, make a page 301 redirect from the old to the new one.
During the move, both sites must be available, that is, fully working two copies (with the same Host directives indicating the main (new) domain).
In google, the move will start from point 4, that is, when there is a page 301 from the old to the new one, it does not know the Host directive, this is only for Yandex.
To make the move faster, add non-indexed pages of the new domain for re-bypass in the same webmaster's office. And a sitemap.