So... I'm not sure if I can hep you. Because I can work good with Toom Boom Solo (I know... it's very old...)
And I don't watch this video tutorial that you say.
But I supose that the solution may be it's the same, because probably you are animating cut-out... or not?
If you are making paperless animation, it's easy. The first frame, number 1, you can go to the frame 3 or the frame 25, and in the xsheet you can do doble click and write 1, and you will see the draw of the the frame 1 but in the frame 25 (for example), also... you don't need copy and paste.
If you are making cut - out, I don't know if I can help you but I can try it... You draw the body in one layer... and one wing in another layer and another wing in the third layer... You have to put all layers in a differents peg... You close the peg to not take casually the layer and make any error. Also... you don't forgot drag the frame 1 until to the end of the timeline. If you can work with flash, that don't be a problem for you, because it's same, there are another way to do it. You click with the right botton of the mouse over the layer and look for the option that say something like "how long... how many frames..." or something like this, I don't remember exacly, but you can say the problem how long time you want to put this frame.. 25 frame.. 30 frames....
When you did that, you close the peg for not take again the draw, and move the shapes just with the peg tools, like in cut out with flash. If the option it's on, then you will can do interpolation automaticly like in flash.
So, I hope that I could help you... if not.. then, I supose that someone here could tell you something.