Templates in Storyline

I have a few questions regarding Templates built in Storyline and the proper way to set them up (to work on desktop AND iPad) and the proper way to save them. 

1.) What is the proper way to set up a template? I know you utilize the slide mater and apply the background as you desire and format the text (Similar to PowerPoint). However, for the image of the background to appear on both desktop and iPad, are their certain peramaters that must be met? (i.e it must be a .png and not a .jpg, should I place on the slide layer as an image or "format background", etc?)

2.) When setting up the colors, is there a guide to let you know what is going to effect what when you change the colors?

3.) How do you save the template correctly so it available again when you open and I can also save it on my laptop for when I work from home? (Basically how do you save the template on two different computers?)

Any input is greatly appreciated!

Thanks!