First add a particle system component to the components section of the blueprint
Set the desired particle system
Drag it onto the mesh so it is "under" the mesh. You will not get any socket options if not "under" the mesh
Select a socket to add to. If you do not add it to a socket it will not properly move with the dino
Drag the particle system into the desired position and set the desired angle
Spawn one in and see your additions