You can use your bonus action to concentrate on
a second task while maintaining background
concentration on a first task.
While holding a second concentration, your
movement is halved and you have disadvantage
on any physical actions (Any roll that involves
using your Strength, Dexterity or Constitution.)
Anything that automatically breaks
concentration will disrupt both tasks. Anything
you roll to maintain concentration has to be
rolled for each task separately.
You may take this feat a second time to enable
three concentration tasks at once, however you
must use your action to maintain the third task
and your movement is reduced to 5ft while
holding all three at once.