Smooch, LOW is leaving interest income in the expense area of the income statement. Since it is income, it shows up as a "negative expense." The reason I know this for sure is that if you look at LOW's most recent 10Q, the income statement shows net interest expense of 77. So they had gross interest expense of 81 and gross interest income of 4, which nets to 81 - 4 = 77.
I do not have a book to recommend. While I learned the rudiments of forecasting in business school, I really learned most of it by doing on the job, aided by the direction of a very smart, very experienced guy who was willing to teach me.
However, I can certainly try to offer you tutelage. For starters, see if your brokerage offers research reports. If they do and have the longer reports, see if you can get one for HD or LOW that has an analyst's model in it so you can see what they look like. I can also see if I can turn up an old model of mine, although they would be out of date and tend to be very focused on certain things.
The modelling process you follow depends on the type of firm and what you are trying to learn. Having said that, my models generally have a page with a summary on it, a page with the income statement and a reduced cash flow sheet, a page that lists out all the bits of a company's debt along with a maturity schedule (mostly important for leveraged firms or junk bonds), and a page that shows how the balance sheet changes over time. In some cases my models are simpler than this, but this is the typical structure.
I would suggest that we look at the model page by page, starting with the income statement page. Did you want to try to model HD or LOW for starters?
"Neither my companion or I carry firearms on our persons. We depend on the goodwill of our fellow man and the forbearance of reptiles."
- English Bob