Workflow in MOSS

It's been 3 years I have been using MOSS but I never got chance of creating a Workflow, nor I did try to learn it :(. The sad part if I have never tried it and good part is its such a great functionality to use.

So I how did I design my first work flow - I used web browser to create it. There is other way to do it - Microsoft SharePoint Designer, and one more way to do it by using Visual Studio 2005 and +.

Questions came in my mind -

1. How to create multi step workflow from browser?
ANS:(use SP Designer)
2. How to edit workflow in SharePoint Designer?
ANS : (File -> Open Workflow -> Select workflow to edit.)
3. How do I add more conditions to a workflow engine?
4. How do I add more actions to workflow engine?
5. How do I embed business logic in workflow?

-S