All of the beginning footage of Frax running away from Ransik is new footage.
Here's new footage of Severax
Here's new footage of Dragontron

This shot is when it goes to Sentai footage.
The up-close shot of a male Bio-Lab Scientist (or whatever he is) is new footage however it has to be so up-close of him to the point that you just see his head, face and his upper torso. It then cuts into more new footage due to Severax walking into a part of the building that has "Bio Lab" written on the wall behind him.
This shot is when it goes back to Sentai footage.
It then cuts into new footage due to the red couch being there.
There's a cut in new footage which cuts into a zoom-out of this Sentai shot
It then cuts back into new footage once you see the Silver Guardian with a headset microphone on him because he's the one that is escorting Mr. Collins to safety.
After Ransik tells Severax "let's get out of here," it looks like there's a quick cut of a Sentai shot of some explosive sparks on top of a building as well as a shot of a Cyclobot firing a tiny Cannon however once you see Eric again then that is when it goes back to new footage.
This shot is when it goes back to Sentai footage.
This shot of Blue is when it goes back to new footage.
Once it cuts to the Yellow Ranger then that is when it goes back to Sentai footage.
After Wes fires the Electro Booster at the C-bots which is Sentai footage, as soon as you see the Blue Ranger again then that is when it goes back to new footage.
However once it cuts back to the Yellow Ranger then that is when it goes back to Sentai footage.
All of the Giant Severax and Megazord footage is Sentai footage.
I can't be 100% sure but it looks like the shot of the frozen shrunken form of Severax falling onto the ground is new footage.
Here's another new shot of the Dragontron in the Bay
The following shot of the frozen shrunken Severax on the ground as Trip places him into a Canister is new footage.

Severax Sentai footage comes from Time Episode 24 and various Cyclobot footage attacking Bio Lab comes from Time Episode 42