How do you do a new install Kali onto a new RAID-0?

The way I understand it, RAID-0 can be used to combine my 30GB internal storage with the built in reader and 64GB MicorSD card to give me 94GBs. I want to use Kali 2020.4 AMD64 as a daily driver on a low spec system. I tell the graphical installer to use the entire drive when partitioning and put everything on the same drive. When configuring the RAID0 array I chose both the internal and SD partitions and ignore the swap partition. When I choose "Finish partitioning and write changes to disk" to install Kali to RAID-0 I get the error "No root file system. No root file system is defined. Please correct this form the partitioning menu." What do I need to do to fix this?

Sorry, if this post is worded a little weird, I'm trying to include as many keywords as I can. I've seen a lot of internet searches for these terms and no clear answers.

I have an Asus TP200SA. It's got about 30.2 GB of internal, solid state storage, two GB of RAM and an Intel Celeron N3050. There's a Micro SD card reader built in. It won't boot from the Micro SD. I also have a SanDisk - Extreme PLUS 64GB microSDXC UHS-I Memory Card (Model:SDSQXBZ-064G-ANCMA). From what I've seen, the TP200SA's internal storage can't be upgraded.