naive question about stocks-using George Weston as an example

Please be nice to me...lol. I want to know why there are so many stock variations in one company. George Weston Co. main stock ticket is WN.

There are 5 or 6 others listed on Toronto exchange too(wn-pc, wn-pd, wn-ne, wn-pa, etc.) .what do they represent and are they better or less value overall? Thanks