Selecting and trimming clips

I’m a long time audio editor new to Shotcut and suddenly faced with doing a video edit of a bunch of talking heads. Over two hours down to a very few minutes. So, my question. What’s the best way to find and select the beginning and end of words (phrases, sentences), with perhaps 45 frames on either side for dissolve, and then assemble them. That’s really two questions. What’s the best way to find those cut points, and then what’s the best way to identify the selections so I can order them on the timeline?

When a clip is on the timeline, it has an audio waveform that makes finding audio points much easier, but trimming shots that are on the timeline seems slow when the clip is some 10 minutes long. (I’m dealing with a panel discussion where each persons starts off with a ten minute presentation from which I need only a sentence or three.) Were I to just grab a rough selection and add it to the playlist, then it’s hard to tell which clip is what as the image is always the same talking head.

Apologies for asking such an elementary question, but any help will be appreciated!

You may drag the in- and outmarks in preview directly after import/open. Regard selecting source (Quelle) and than drag the in- and outsliders.