Hi Andrew
I'm glad to say that you actually can! :)
In your campaign, click the "gear" icon that appears in the tabs above the chat section. You'll see a section called "Macros"
Click "+ Add"
In the popup box, give it a name (If you'd like a button, use a single word)
for this example I'll call it attack
Now, in the command(s) section, enter in your script
/roll 1d8+1d4+2
If you want multiple commands, enter each one on a separate line.
Now, click "Save Changes"
At this point, you're required to turn out all the lights, and say "Hail Cthulu" three times
Now, you'll see a checkbox that says "Show macro quick bar?"
toss a checkmark in there
and check off your macro in the list as well where it says "In Bar"
You should now get a thin strip along the bottom of your screen, and any macros you check off will appear there. Pretty gorram cunning, doncha think?