New computer

Hi.  I just purchased a new computer.  An IMac.  I'm not a big fan of laptops so this is a desktop.  I'm slowly learning the ins and outs of using it.  If anyone  can offer any support, that would be great.  My next step is to download my pictures from my old PC to a thumb drive and then upload them to the Mac.  Anything I should be concerned about or process I should try.  Totally different but I'm loving it so far.