how do I attach a staccato to a note in Garageband '11

Everything that Léonie said is correct - but in this case I would just (1) shorten the note in the piano roll view (after all a staccato is a short note) and (2) lower the velocity until it sounds light enough. That should work, especially with a piano instrument (you didn't specify what instrument you are using.)

I'm trying to make a cover of the entertainer in Garageband using the score and effects, but I can't seem to figure out/find on the internet any way to attach a staccato in Garageband '11.

The score view in GarageBand is very basic. You cannot add instrument articulations like "staccato" in the score.

Many instruments can be set to use a particular articulation, depending on the velocity, mod wheel, expression, etc. These settings are specific for each instrument. You can edit them in the automation curves in the Track Editor.

Some JamPacks have readymade instruments that play using a specific articulation, like "Xtra Brass Ens Staccato" or "Extra Cello Sect Pizzicato".

If I need a certain articulation, I try to find an instrument that plays in the style I want, or I write the score in an external Editor like Finale and import the midi file, or start from a software instrument loop that has the articulation I am looking for and copy the automation curve settings.

"Staccato" on a keyboard instrument should be captured, if you enter the notes by playing the tune on a midi keyboard that transmits the velocity.

Regards

Léonie

Touché. :-) So it's even more true - even an old fashioned real acoustic piano has just two parameters for expression: velocity and duration (and of course early or late onset, but that's not relevant here.) So there's your lightness.

That should work, especially with a piano instrument (you didn't specify what instrument you are using.)

Yes, "The Entertainer" will sound great on a piano played this way 😁