More tag doesn't work for me

Hello, First at all thanks for this great theme and sorry for my english. THeme : simple catch pro I ve been searching for hours and couldn't make the button more in editor to work on page. ive tried to add manually <!--more--> in text but nothing more. I explain : On my start page, i have text and i just want to have a read more/ continue reading button to expand text . i ve put the more tag in editor, but it doesn't show on my page. i've tried to change the layout from full content to blog but nothing work. strange, if i use the next page tag, it works. Ive search on forum but didn't find anything to help me so sorry if it was already asked. Im quite far to be w standard user to wordpress. Maybe i just forgot something basic. thanks for your help Cedric