Document - this is a word style document.
In the top right hand corner they will be a button with the words share. Click the arrow next to it and select publish as web page. Then press start publishing, this will give you two codes the link to the page or the embed code. Select the one you want then put it into the html of a post on your blog and there it is.
Note - if you want it to change on your blog as you change it on your google doc leave the tick in the "Automatically republish when changes are made" box.
Presentation - The same as document but press the embed/publish button instead. You can embed the presentation with the code given and put a link to the page by copying the link under the word "Your document is publicly viewable at: "
Spreadsheet - This is the same as the document but you can make it into many different things. You can put a link, embed it, make a picture etc.
Drawing - identical to document
Good luck with Google docs.
