How do i customize event + page and calender appearance?

I would like to customize a single event page and a calendar as well.

For the single event page, I would like make like the screenshot. basically 2 column layout, event information on the left and the map on the right. and I would like make time, date, place and address on each line.

How do I make a new template file without hurting the core plug in data, so any future update won't break my template?

I can do CSS and very basic PHP. is there any list of variables for date, time and etc so I can echo out on my temple?