Grouping taxonomy terms in views

There is a website http://bryansk24.ru/gid, take a look at how the taxonomy terms are grouped. I need to implement something similar on my site. How can this be achieved? There is a taxonomy vocabulary (name: organization directories) and the terms have different levels of depth, such as 1.1, 1.2, 1.3, 2.1, 2.2, 2.3, etc. I tried to extract everything through Views, but it pulls all the terms without grouping them under the first level.