Creating a blog page is easy. avvin is using native Blog settings. Just create a new page for blog and set it as "Posts page" under Settings >> Reading section. See screenshot given below:

Now start creating new posts by going to "Posts" section

avvin theme supports 10 post formats. You will see all Post Formats as tabs to select. If you can't see tabs than please install CF Post Formats plugin. Here are list of all supported post formats with details:

• Standard post format:
  
• Aside post format:
  
• Audio post format:
  
• Chat post format:
  
• Gallery post format:
  
• Image post format:
  
• Link post format:
  
• Quote post format:
  
• Status post format:
  
• Video post format: