When I have a post and I want to attachment say three images one above the other. How can I do this? Also if I want the images side by side on the same row. How can I do this?
Just attach the files to your post. Everybody can see them under you post.
if you want to include images inside your post you have to do it manually by adding an [img] tag to your post and the URL of the attachment.
I do that often to make my posts easier to read, but I don't recommend this for normal users.