Transfer from old iMac to new iMac
What is the best, ie safest and most complete, way to transfer data etc from my current (old) iMac to a new one I am picking up this weekend?
Old iMac is 21.5 inch Late 2009 running on High Sierra 10.13.6
I have Time Machine and have backups on two separate external drives (just to be sure i don't lose anything).
Thank you.
iMac, macOS 10.13