Hello David.
I am not sure which tutorial you are referring to.
Have you looked at @swarfendor437 's unofficial manual for Zorin 15, which includes advice on partitions and installation.
Will your new computer have a SSD or HDD ?
The EXT4 file system is journalling type and will not be good for your new SSD if you have one of those in place of a HDD. If you have SSD then use a non-journalling file system e.g. EXT2 to save wear to your SSD.
I have always installed Zorin with these partitions:
/ (root)
/home
swap
Note: your swap partition should ideally be set as 2x RAM capacity of your computer. e.g. 4GB RAM then 8GB swap.