please i need help sending keystrokes for sabertooth motor controller w/ apc220

[armenvegas]

thank you in advance for reading...
I am trying to use keystrokes

w=forward
s=reverse
a=left
d=right

for my dimensionengineering sabertooth 2x60 for a wheelchair
I have purchased apc220 modules.
is there an example I can follow?

thank you