The easiest way to assemble and link the program is from the Programmer's WorkBench (PWB). From the Options Menu, select Link Options and choose OS/2 Application. When you select Build from the Make menu, PWB calls ML and LINK, passing the proper options.
From the command line, type
ML hello.asm
The next section discusses how to “bind” the program—that is, convert it so that it runs under either DOS or OS/2.