Was just looking for this and found a solution, although very hard to find, so I am relaying this so it can get out more!
Once you add a variable to control rig, it is then accessible within your animation blueprint. If you don’t have an animation blueprint yet, there is now a “ControlRig” node that you can place in the AnimGraph. You can then click on the node, and in the details panel, at the bottom, you can assign your ControlRig class, and then all your variables will appear as optional checkboxes. Enable the ones you wish, and feed your data through the animation blueprint as normal. If you haven’t brought data into an animation blueprint before, just go into the Event Graph, you get the parent actor, cast to your character/actor, set it as a variable, and then you can “get” your character/actor and pull it’s variables, and feed those into the ControlRig node!