Deleting all the same but non-contiguous color to transparent PLUS how to change the style of grouped lines.

Hello, I have two questions: Since now I'm trying to find the thread where I previously asked about making all the white but many non-continuous areas AND the background of a document transparent with one or two shortcuts. Second is, and I used to be able to do this with Coreldraw 12 and X5 but I can't find how to do it in X8. - - How can I change the style of all the lines I have grouped at the same time rather than change the style of a line one at a time. Are my tools not fully implemented maybe? Thank you so much! J J