This is a really open question but I am not sure how or where to start. I have a main SharePoint Online site, corp.sharepoint.com, which has a menu system and is fully operating. I created another site, corp.sharepoint.com/sites/
dev which displays the a screen (see attachment) that looks different from the original site. My question is how do I go about getting this site to have the same look and feel as the main site (corp.sharepiont.com) so that I can use it as a test site. Being able to add additional pages, web parts, etc. and play with things before I put them in the live site?
I really appreciate all of the help and assistance.