Change Content Of Tabbed Sidebar

Hi folks,

I’m playing around with the Swift theme. It seems to have what I’m looking for, especially the magazine or grid-style posts.

One thing I’m rather stuck on: I want to change the default tabbed sidebar’s content of Posts, Comments and Tags to something like Recent Posts and Popular Posts. I don’t see any option within the theme to change those, so I guess changing the coding is in order?

If I’m to do that, what do I look for? And how will I achieve the desired effect above?

Any help is appreciated. Thanks.