Hi Tamerlan. These two articles discuss creating navigation buttons for your doc. Basically, create a header section where your navigation buttons will go. I use the Doc Explorer pack to get a table of all the pages created in my doc and build those buttons. You can create a dynamic tab menu for each page via filtering this table.
and
Here’s an example of my template page lay out with buttons. It’s not as pretty as Clickup or other common SaaS but I have more flexibility to create the same functionality for much less than they charge (especially per seat).
Hope this helps.