First of all, I'd like to say that I'm what you would call a "newb". I've only just started to understand how to navigate this forum, I'm only now really starting to wrap my head around all the lingo; so I apologize in advance if I've posted this question in the wrong area.

I typically use *A flights currently, as I live in YYC and am an Aeroplan member, but in March I'm flying to MNL and one of my segments on the return is with CX. MNL-HKG -[Flex, M]. I'd like to collect points for this segment but I don't currently have any OW frequent flyer plans. Which should I sign up for?

Also, what would be my best bet for upgrading that segment to First/Business class, and how would I go about it?

Any advice/suggestions would be most helpful! (sorry for my "newbness").