Changing type on Parallax Homepage - size and font


I would like to make the title and subtitle bigger on the first section of my site. I tried to add code from an older, similar question on this forum, but it didn’t work.

Also, though the theme font is very close, would it be easy to change it (just for this title and subtitle) to match my logo? The font name is Poiret One.

And: I’m a beginner and will likely have several more questions. Do you prefer them grouped together, say, by section? Or one question at a time?

Thank you in advance for your help!