Make template, etc are grey !

Did you define your local site folder yet?  That is a very important first step.  Otherwise, DW cannot manage assets for you.  Go to Site > New Site >  and tell DW where your project folder resides on your primary hard drive. Once the site is defined, you should have no trouble saving the HTML file as a Template.dwt.

Nested Templates are a bad idea and very messy to work with.  I cannot think of a single situation where you would ever need much less want to nest Templates.   Your time will be better spent creating a sitewide stylesheet that covers all your site requirements.  Add Editable Regions for content that will change from page to page.  And add Optional Editable Regions for elements that you use in some but not all pages.  Avoid nesting Templates at all cost..

Are you working with a Defined Site?

https://helpx.adobe.com/dreamweaver/how-to/define-a-dreamweaver-site.html

Not sure what you mean by "selection tool". To turn text into links, you highlight the text, then in the HTML section of the Properties window, add a URL to the Link field. 

If you're new to the recent versions of DW, it's possible you're trying to edit in Live View, which is different from the way things work in Design View.