Change the text contents of a moving banner in a video clip

The workflow if you are new to After Effects:

1. Spend as many hours as necessary learning the UI, workflow, and compositing techniques required to produce professional composites on shots with moving cameras, moving objects, and changing lighting in After Effects (average is 40 to 100 hours)
2. Purchase Lockdown (the least expensive full-featured mesh/3d tracking plugin available now
3. Split the footage so you are only working with the frames that have the moving banner
4. Motion track the Moving Banner
5. Create replacement banner artwork
6. Apply the mesh tracking data to the replacement banner you have created
7. Add as many other layers to the comp as required (I'm guessing about 3) to make the composite believable
8. Render the Replacement frames using the High-Quality Output Module preset in the Render Queue
9. Edit the final movie in Premiere Pro to finish the project

There are tutorials on AE Scripts that demonstrate an efficient workflow for using the Lockdown plugin. You could also use Mocha Pro or a combination of several other 3rd party effects, but Lockdown will get you closer to a professional-looking replacement banner for less money than any other workflow I can think of.

There is no "minimum fuss" approach if you want it to look good and quite frankly for a beginner this is a terrible shot to pick. Due to the camera and banner moving all the time, the complex lighting situation, the deformations of the banner and other factors this would require a lot of hard work even for an experienced VFX artist. In any case, study classic corner pin tracking tutorials to even get an idea what awaits you. Again, you're in way over your head if you have zero experience and don't even understand basic workflows.

Mylenium