How to increase the width of content writing on the home page of the responsive

Hi, this is my site http://www.wgdigitalimages.co.uk and I’m using responsive theme. I used to have old version of responsive theme but recently I updated to the latest and and lost all the changes I made on the old one even thought I created a child theme. Now on the home page I am being unable to write the texts just under the video(I like to write the content full page, I mean increase the width on the texts and be able to write below the video of the home pages as well. I also lost home page tab and I don’t know how to put it back again. Can anyone help please.
Thanks