Realnews – remove author's name

Hi,
I am very new to wordpress and installed realnews theme by Ridwaan. Its an awesome theme except I need to make some changes.

—I need to remove the author’s name from the posts (posted by …)- https://nsliy-interactive.org/2013/12/03/what-does-the-sheep-say/ – how do I remove the author’s name? I tried using edit.css but it doesn’t work. May be I am editing the wrong elements.

–I need to add map and the markers on the map should be linked to posts. I installed the Nomad map plugin but it slows the site so much that to add a new category and I need to deactivate the plugin to continue working on the site. Could someone please recommend a fix or another plugin that I could use?

Thank you so much for all your support.