This screenshot shows the Create Tablespace wizard - Step 2 (Add Datafiles).
"appts.dbf" is entered is the Datafiles field and the + (add) button is being clicked.
x (delete) button
File Size: 100M
Reuse Existing FIle: (unchecked)
Auto Extend: (checked)
Increment: 100M
Maximum FIle Size: Unlimited
There are five active buttons labelled as Back, Show SQL, OK, Cancel, and Next.