Welcome!
Since you already have a ZFS pool on your system, you want to make Incus use a dataset in that ZFS pool. See example at Help with Setup - #2 by simos
Therefore,
- Name of the new storage pool [default=default]: (you may leave this empty to use default, which is just the local name that Incus will be using for the name of the Incus Storage Pool. You can put anything here. )
- Name of the existing ZFS pool or dataset:
zfspool/incus
Incus will create the dataset for you. Do not create it manually.