First of all, a huge thank you to @Ragtime_Kitty
for humor))) As they say, what question such and the answer is...
Now, to be honest, you have now a horizontal menu, and likely on the layout vertical menu there no good.
As for the menu, believe me here EP and. Rather, this is an important layout. Accordingly, the need for knowledge of html css js. If you find it difficult to deal with these languages and write your code, you can try ready-made plugins or snippets codes.
Here, the vertical menu plugin https://wordpress.org/plugins/bellows-accordion-menu
Then you can use Uber Menu. Universal plug-in.
Here, ready snippets - https://bootsnipp.com/search?q=vertical+menu
Here, more examples - https://freebiesupply.com/blog/css-menus/
However, here you still need knowledge of coding, in particular Walker (see WP Codex - Walker) + html + css + js