Delete or add measures ?

Sure:

To insert empty measures in a container, select the container first, then mark the desired span on the time ruler and use Container >> Make Room. Be careful, because this affects only the containers inside the selected container. In most cases you probably want to select the root container, so that all its children move to the right to make room.

If you want to insert empty space into a single phrase, you need to copy/paste empty measures in the Figure parameter.

The time signature is part of the Scheme parameter. You can assign it to any container. It is global and will last for the duration of that container.

Christian

EDIT: Forgot to mention deleting measures. You either delete them from the individual Figures, or you split a container (Edit >> Divide) which divides it at the selected ruler position, and remove the portions you don't want.

BTW: If you have very long phrases in the root container only and want to structure your song, you can add empty containers, arrange them as you see fit and make a snapshot for each. Skip the parts you don't want. Move the containers around to get the desired song structure.

Don't forget to delete the original phrases from the root container when you're done. They might get in your way later on. Or even worst: You will find yourself editing these and wonder why that has no effect at all ;-)