To update your blog posts, you must first login to the 'Blog Posts' section on your profile page. After logging into this section, you can continue your process by selecting the blog post you want to update.
Blog post product detail screen
After selecting the blog post you want to update, you enter the blog post detail screen.
Blog post update screen
You can complete your process by making the changes you want to make from the update screen that comes after clicking the 'Update' button.