how do I edit Custom Taxonomy Archive pages?

I'll describe what I'm trying to achieve, and will appreciate your guidance.
* I'd like to have an archive pages for any value of my new custom non-hirarchial taxonomy: Stocks.
* When going on this page (e.g. , I would see a page built according to my defined template: list of posts of various new custom Post Types, my selected widgets on the side, and so on.

* How do I edit the template for this "stocks" taxonomy archive pages? I'm using CustomPress. Is there a complementary plugin, or do I have to edit .php pages?
* How do I set which widgets will show on "stock" pages?
* How do I edit the layout of the posts (in my new post types) which present on the custom archive template?

I wish there is a graphical way to achieve this, without needing to edit .php files.
Appreciate your help.