@Robert Trim
Editing in Scratch can be a bit wonky due to the slot based nature of it all, but just a quick look at addressing some of your points. (Also keep in mind a firm understanding of "Fit In/Out" and "Fit Slots")
- Cmd + I = cut in scratch - it basically creates a new slot. Keep track of your In and Out points for that media and the slot length though. Can also get to this under Edit > Timeline > Slot > Insert
- Dissolves are controlled under Edit > Video > Transitions to adjust both ends of the dissolve that bleed into the next or preceding slot.
