To move your files from SkySafari 5 to SkySafari 6 you will generally use the "File Sharing” feature in the iTunes desktop app. The procedure is slightly different depending on what version of iTunes you have so if you are not familiar with this, you might do a web search for "iTunes File Sharing" for instructions.
If you have been storing your files on iCloud in SkySafari 5, and you have iOS 11, then you can avoid iTunes File Sharing by going to the iOS Files app and opening iCloud Drive > SkySafari 5 (Plus or Pro). Select the file you want to import and then tap the share button. From there, find SkySafari 6 in the list of apps you can share with. That should import the observing list or settings file into SS6. Note, however, that you cannot import your Equipment that way.
If you don't have iOS 11 or just want to use File Sharing because you have a lot of files to transfer, it should be a simple operation of moving the files from iCloud Drive on the Mac into SkySafari 6 using iTunes File Sharing.
If you haven't been using iCloud, you will first have to use iTunes File Sharing to copy the files from SkySafari 5 to your desktop and then copy them to SkySafari 6.
You will probably want to copy the following
All .skylist files
All .skyset files
At this time there is not a way to move your custom locations from SkySafari 5 to SkySafari 6. You will have to manually recreate them in SS6.
IMPORTANT: After your observing list and settings files are imported into SS6, they are deleted from the Documents directory because they are now stored in the database. If you add the files to the Documents directory a second time you will get duplicate imports. Duplicates file entries will also result if you add the files to another device that is also synced via the same LiveSky.com account. You need only add the files from SS5 to SS6 ONCE, using any one device. The files will then be synced to all your iOS devices using the same LiveSky.com account.