Welcome to the forum.
For a solid, color "block," you can create a Title, with a rectangular Shape. You would then size and position that Shape in the Titler (Tile Editing Panel), to suit, adjust its color there too. Just drag that Title to your Timeline on a Video Track above your Video, and adjust the Duration, as needed. Then, as Neale points out, adjust the Opacity, as is needed.
In this example, there is a rectangular Shape (that goes from Frame edge to Frame edge, with reduced Opacity, below the Text Title, "This is Heathrow:"
Hope that helps,
Thanks to both of you. I was looking for color mattes, which is what I meant by solid blocks of color, a layer. I was wondering if I could ask two more questions: since Crop kills some pixels and degrades the quality a bit, I prefer to use the letterbox template created in Photoshop. The issue is, I have been having difficulty in trying to reposition the clip beneath the template, to adjust the way I want it to while keeping the template consistent throughout. How do I slide the clip up and down? Now, looking at your interface image, Mr. Hunt, I realize that in my version, the timeline looks like [video1/audio1][video2/audio2][video3/audio3]...and so on, and I was wondering, how can I consolidate video tracks separate from audio tracks, as in Final Cut?
First, just the Crop Effect should not degrade the Color Matte, or anything else. However, if one then Scales up, there will be degradation.
For Position, just Select your Color Matte, or Template, and go to Effects. If you have not added any other Effects, like Crop, you will see the Fixed Effects, Motion, Opacity, Rotation and Volume if you also have Audio. Go to the Motion Effect and twirl it open (little triangle to the left), and you will then see two Motion Effects, Position and Scale. Make sure that the CTI (the Current Time Indicator w/ the red edit line - also referred to as the Playhead) is on the first Frame of that Matte, or Template, and then use Position to move it to the desired location. This will add a single Keyframe at the Head (first Frame) of your Clip. You can adjust the Position in several ways, such as dragging the Bounding Box, or by clicking and then typing in the coordinates for Vertical and Horizontal, or by click+scrubbing the values in the coordinate boxes. I like typing in the values, as that is what I find to be the most precise.
PS - as you also mentioned Opacity, above, if you need to adjust that, follow the same steps, but just go to the Fixed Effect>Opacity, and adjust that too.
Note: all of those adjustments can be Keyframed, so that they change over time, but if I read your post correctly, you do not need that, in this case. Just keep that in the back of your mind.