existing folder as DataSheet

[naeyder]

Hello,
I have set up my old NAS with Debian myself.
I have now bought new hardware and used TrueNAS Scale. After a bit of trial and error, I have now moved all the files several times and created the disks (1x 16TB, 2x3TB, 1x 4TB) as datasets.
On the 16TB disk I created a dataset called "pool16". I pulled the data into the pool using ssh and also adjusted the user (in this case apps:apps and set the rights, but there is still a "+" behind the rights in the pool). I thought that these would then be automatically recognised by TrueNAS Scale as a sub-dataset. Unfortunately not.

Show : Datatree for explanation

File tree in TrueNAS:
-pool16
.....|_ Entertainment
..........|_ Download

File tree in bash
-pool16 (rights 775 and app:app)
.....|_ Entertainment
..........|_ Download
.....|_ F 1
.....|_ F 2
.....|_ G
.....|_ S 1
.....|_ S 2

Hence my questions:

1. Is there a way to import the existing folder as a datasheet?
2. Is there a possibility to change the size of the dataset "pool16"? There are supposedly only 7TB available here (of actually 14TB available on the disk).

Many thanks for your help!