Hello and welcome to the forum,
This tutorial: How to create a skin (using tables)
walks you through step by step all of the information that you need and it creates a vertical menu using the Solpart Menu rather than the tree menu. All of the code is available for download with the videos.
Dreamweaver is fine to use. I have demonstrated the skin tutorials using Visual Web Developer Express as it is a free programme with good features, but you can use any programme you are comfortable with.
If you are new to DNN and creating skins I would suggest working from Issue no 5 & 6
through to the latest issue as each issue builds on the knowledge from the previous issues. - If you are completely new to DNN you will get a good grounding in the functions of working with pages, security roles, modules etc by starting at Issue no 1
Hope this helps to get you started, thanks,