Text narrative overlay over visuals

I need to present a certain topic through visual presentation. The visual content will be JPG photographs, CAD animations in JPG format (alternatives available), CAD drawings in JPG (or others) and AVI movie clips.

The narrative is presented as text blocks (also in JPG or other format), interspersed with or overlaid over the visual content. The text letters alone must be visible and appear to be ‘on top’ of the pictures.

I’ve tried to add an alpha channel with GIMP, and also different combinations of Blender ‘add’ or ‘alpha over’ functions with limited success. Lack of experience, no doubt.

An experienced Blender user can probably do this in his sleep. I’m a newcomer. But I have to get this video out and I am running out of time.

In general the tutorials are unsatisfactory. Brevity killing clarity. No-one works from a structured text. The skill level of the presenter is self-evident and the ‘story’ comes across, but no step-by-step stuff that a newcomer can latch onto without many replays.

Any help will be highly appreciated.