Neither of these plants will be killed by improper pruning....
Just whack off what you don't want and observe where the new growth emerges. Then you will know where to cut the next time.
That is not an ivy it's a pothos...
And if you copy and paste the url of the site where your pictures are into the line that says "Optional link URL"....everyone can see it with a lot less problems.
Linda C

And yes, the pothos should root in water. Or stick a pot of soil under one of the vines, pin the vine to the top of the soil (an old fashoined hair pin or bent paper clip) and keep moist.

Thanks! And thanks for clarification on the pothos - like I said, I'm new but I do enjoy gardening. It's very relaxing for me and has become one of my new favorite hobbies!

do i need to remove flower on hens and chicks to prevent them from dying?

They won't die if you don't remove the flowers....and they will re seed....but I think those flower stalks look awful, so I cut them off.
Linda C