There's two steps to getting a club table in the student centre.
First, you have to go to the MUSC office in the 2nd floor of the student centre, in room 222 and fill out a document. Then, you visit the website and apply for a table.
This is the Reservations page of the MUSC website. Click whether you want a Info table, a bake sale table, a banner space, or any other type of reservation. From there, you fill out the info page and wait for them to contact you (they're pretty quick at replying).
And that's that! Like the above poster said, you do have to book it in advance.
Have fun and good luck getting people's attention