Get yourself a tester and determine which set of 3 is the hot wires(note, there may be more than 1 set of hots in this box, test all 3 wires for hot before you do anything). The hot will hook up to the terminals labeled LINE. Do not use the stab in holes, use the terminal screws on the side. The 2 other sets will be attached to LOAD. Again, do not use the stab in holes, use the terminal screws on the side. It will be very tempting to attach one set to the LOAD holes and the other set to the LOAD screws but, you really don't want to do that. You will want to attach a pigtail, combining 3 wires under 1 wire nut and attache the pigtail to the LOAD screws.
If by chance the old outlet had the bridge tab removed then you might of had an outlet where one portion was constant power and the other switched power. If this is the case, you'll need to attach your wires completely differently.