Hello,

From answers to previous similar questions on this site, I'm not sure you can get your tickets printed at the desk in Brussels.
If you are refering to a travel booked for 9th and 10th of April, both are E-tickets, which means you can print them yourself.

On the oui.sncf website, top left 'my bookings / mes commandes', enter the 6 letter reference found on the confirmation e-mail you recieved after you booked, and your name. An error message will probably say that you didn't order on this site. Then add the train number and the date of travel, you will then get the details of your journey and a link to a pdf file so you can print your tickets.

If you haven't got acces to a printer, you could also download the sncf app and store the tickets on your smartphone.