Want to place ads here, which template?

[thunderforceken]

Which template do I need to edit to add Adsense ads in the circled portion? Also can I ad conditionals to have different content adsense ads on different forums so they reflect the topics better? Thanks in advance!

[WhaLberg]

Navbar.

[Dismounted]

Yes, in the navbar, just after the part where it has the navbits.