How to make the drop-down menu like this?

[hyenaond]

I want to create a shop to sell pet products, but I think I need css codes to do what I want in the dawn theme. What I want is for the menu drawers to look like the one below. To be able to slide and open sideways when switching between them.

Ps. The yellow themed one is my own shop, the other is the one I want to mimic.

Thank already.

[BSS-TekLabs]

You can do that by dragging and dropping the child "Menu items" into the parent "Menu items". This will help you create dropdown menus easily. @hyenaond 

- Please press 'Like' and mark it as 'Solution' if you find it helpful. Thank you.

[hyenaond]

I have already done this but it's not my problem's solution. I wanted to turn the dropdown menu into a hover effect and show it as a window on the right side like second photo.

[Benjamen]

Hello 👋

A mega menu with a side drawer and hover effect can be achieved with Meteor Mega Menu (if you're open to a no code solution). You can take a look at how your menu could look here. I'd suggest looking at the "Amazon" template as it would do exactly what you're wanting PLUS it supports images.  
I hope this helps 😊