From your event dashboard (Dashboard->MyDOs->your event) clicking on Blog will take you to the event's blog section, add your comment where it says Blog Here and click Post.

From your event dashboard (Dashboard->MyDOs->your event) clicking on Photos will take you to the event's photo section, then click on Add Photos to upload your photos.

From your event dashboard (Dashboard->MyDOs->your event) click on Invite to send invitations with a customised message to your friends to join you. You can send invitation to your Friends who have already registered on CharityDOs or to email addresses of your other friends.