How to link secondary sites to the main one?

Question

WordPress

Greetings. Let's get to the point.
There are sites:
1) site.com
2) site.com/en
3) site.com/lv
From the main (1) transitions to (2) and (3) are allowed and available.
However, neither (2) nor (3) can go to the main site (1).
What have I done wrong?
I'm trying to organize multisite support)
Thanks for the answers!
Sincerely, Alexander.

Answer 1

Well, this is your one site, and these are its pages, right?