by "screwing up the coding" do you mean that it messes up your page? I'm going to assume that you're working in splitscreen mode (half html code / half design mode) since you made reference to code at all. When you format your text, are you using the "Properties" toolbar (found under the "Window" tab along the top)?

There are tons of ways to put the text where you want it to be on the page (tables, stylesheets etc) - I've gotten partial to stylesheets, but at this point tables would probably be better for your needs.

do you have the pages uploaded anywhere so that it can be viewed? it might be easier to pinpoint where you're going astray in your page is it could be seen.

for your second question, creating a template is just what you need to have a consistant top and bottom  on all of your pages (provided they all drew from said template!)

lastly, and I hate doing this (telling people to do something another way instead of just helping them) - but you really might want to consider using ImageReady for graphics prep and use DW for the HTML/Page building stuff - lol there I said it