By default the Total theme displays custom excerpts for the blog entries. If it’s showing the full text instead it’s because excerpts have been disabled. Log into WordPress then go to Appearance > Customize > Blog > Archives & Entries and make sure that “Auto Excerpts” is enabled.
Note: If Auto excerpts is enabled but it’s showing a lot of text, please double check the “Excerpt Length” setting as well to make sure it’s correct. The length is based on “words” so if you enter “40” it will display 40 words.