Help with the Menu

I’m newbie here so sorry if I’m posting this in the wrong place … Please guys I have a problem and I wonder if anyone can help me … I have zero knowledge about programming. So please explain in details …

I have problem with the shop menu Your Dental Supply … the menu is long and ugly just want to change it to wider menu which is divided into four columns

My theme is the mearishop and I’m using WP … I would really appreciate it if you can help or at least if you can direct me to anyone who can help … such as the mearishop support … It does not seem like the mearishop is still available.

Sent you a pm. Thanks!