To accept, you email: fellowships@sshrc-crsh.gc.ca - takes a day or two to hear back, but they confirm! If, for some reason, you need to change the award date (as I had to move the award start from May 1 to Sept 1), you email them there.
Also - congrats to you and everyone who got it - and for those who didn't, there is next year! I wasn't successful the first time last year, but reworked it, got a bit further in my topic (critical data studies/AI embodiment + data de/colonialism) and got the CGS-D this year. The whole process was a beast though. I'm glad that this forum exists!