First, take a look at the post in your feed and scroll to the bottom of it.

To view the full post, select "Continue Reading" on the preview. This will bring up the entire post for you to read.

To comment on the post select the speech box with the three lines on it at the bottom and you will be able to type out and submit your comment.

To like a post, select the heart icon at the bottom of the post. If it highlights pink, that means you have successfully liked it!

Note: The process is the same whether you are in the preview or full view version of the post to comment on and like the post.