Hello all, this is my frist post on this site

Today I discovered that I want to start collecting miles for future travel. So I have basic questions which I can't find answers to.. hopefully you can help.

Mostly I fly with Lufthansa, British Airways, Air Canada, Eurowings, or LOT.

Now if I wanted to collect "miles" which should I collect?? is Frequent Flyer miles for every airline?? I know for a fact that "Lufthansa" airways has their own system called "Miles & More" is this their own system seperate from Frequent flyer miles?? or is it all the same?

I live in canada and all I see is everyone use frequent flyer miles, but most of my flights are made to Germany or Poland. What should I start collecting?

How does this all work, if I sign up for "Miles & More" will I be able to add miles with every purchase I make just by handing them my card? Will I get a card or does this work through Credit Cards only?

As you can tell I am somewhat confused.. but I really want to start collecting and start earning free flights.

Thank you in advance to anyone who answers my questions.

Cheers

Luke