Yes, it is usual to copy personal folders/files to ext drive and then copy from that to new laptop. However if new W10 has only SSD drive you may want to consider it's GB size. It may be more practical, if you have lots of data, to keep some on the ext hard drive instead of filling up the SSD. OR if new laptop has SATA hard drive it may have partitions, one of which is for Data/Documents.
If you want suggestions for best set up, post back with details of the hard drive (and it's partitions) that is in the new W10 laptop.