How can i chage the layout of my prestashop 1.7 default theme?

[ayez1389]

Please i am looking for a way to make the following changes to the mobile view of the default theme of PrestaShop version 1.7. Please look at the attached image

I want the search bar which i labeled (1) to replace (2) and (3) and also i want (3) which is contact information to replace (1). I want only the phone numbers to appear where the search bar is. I have tried repositioning the modules but i can't seem to make changes that will affect only the mobile view. I have also tried editing the source code of the header.tpl file (public_html/jFooodMart/themes/classic/templates/_partials/header.tpl) and it not only seems wrong but changes don't even seem to take effect. Is there any way i can go about it. It will be highly appreciated.