Hi. I bought a 2017 iMac with a 500GB SSD on Black Friday. I also bought a 1TB Samsung T5 SSD for external storage. I just received both last night and I haven't open them yet. I am upgrading from a 2011 iMac with an HDD so this will be my first experience with SSDs and will be the first time I use a Mac with APFS. I don't plan to do a data transfer from the old iMac. I will back up the photo and music libraries from the old iMac to external HDD as a back up but I plan to set the new Mac as a clean new computer and use itunes match and icloud photo to get my music and pictures in it. I have a few questions that hopefully somebody can answer. Because the computer was custom order from apple with an SSD will it be factory formatted with APFS or will it have HFS+ and I will have to convert it? Do I have to format the external SSD and set it to APFS before using it on the iMac or is APFS just for internal drives (I heard is good practice to format the external SSD before using it on a Mac regardless of file system)? Is it good practice to set the locations for the iTunes library and the photo library to the external SSD so I don't fill the internal SSD? If I do, do I have to do something before I open these apps for the first time so they don't default the libraries to internal storage, is it all done when I first open them or do I have to change it on the settings after it has already created a library? Thanks in advance for any information and I would also appreciate any other tips on what to put on the internal drive and what to keep on the external.