This front load washer is not specifically designed to have starch added during a normal wash cycle. The water level used in this type of washer will not likely distribute liquid starch on the garments evenly and effectively. The fabric softener dispenser is not large enough to dispense a significant amount of liquid starch solution into the washer during the rinse cycle. I recommend using spray starch instead of adding liquid starch during the cycle.
The only way that I can imagine that you could possibly add starch would be to select Spin Only and add the Extra Rinse option after the load is finished. This will run an extra rinse cycle. Add liquid starch through the detergent compartment in the dispenser. Try this method to see if it works for you. You may have to experiment with the amount of starch used. If the water level is high enough to properly distribute the starch, this method may work. If not, then you would have to use spray starch as noted above.