Doing a new Post in Composer

I am very new to this whole website building thing. I have been reading the instructions online but am simply struggling to learn how to do a new post on the newspaper theme? From what I can tell, I start making a new post under the Post Tab on my dashboard, but then I struggle with knowing how to edit how the post will look in TD Composer? I read the instructions on how to download templates from the cloud library and apply them on a post (or as the default setting for all posts), but I can’t figure out how to edit the look of my post–am I supposed to write the post only in TD Composer somehow or write my post through the Bluehost Dashboard under the New Post tab and then edit the look in TD Composer?

I just feel a little lost because I can’t find a step by step of how to do a new post while using all of the tools that the Newspaper theme has to offer; like most of the templates have various places for multiple images and blocked quotes, but every time I apply one of these cloud library templates to my post (which I’ve written from my dashboard under the Post tab), my post just looks odd and i can’t figure out how to edit it to make it with my post in it? I hope that makes sense. I’m sorry I’m so novice at this, I just really want to learn how to make this work and the instructions online are not very thorough. Any step by step help would be greatly GREATLY appreciated. Thanks in advance.