To create additional partitions within MSDOS 6.22, use the fdisk command. fdisk is an "external" command - meaning not part of command.com and has its own executable.
6GB disk and 2GB partition for MSDOS 6.22 seems unnecessarily big. During the time when most desktop PCs ran MSDOS, Windows 3.0/3.1/WFW 3.11, hard disk capacities were commonly in the order of few hundred Megabytes (MB) and having a 500MB disk would be considered high capacity. It is probably best to go with the recommended 2GB disk and create smaller partitions out of it.
Here's a comparison of "low cost PCs" from an old PC Magazine Feb 23 1993 issue
https://books.google.com.sg/books?id=4RN8nH8oZ2QC&lpg=PA123&pg=PA168#v=onepage&q&f=false
For $1948, Dell System 486P/25, 4MB RAM, Conner 170MB IDE hard disk with 32KB cache, 1.44MB FDD, 800x600 14" monitor with 60Hz refresh rate, MSDOS 5.0, Windows 3.1