Anyone park at Murcia Del Carmen Train Station?

Evening all

I have bought 4 return 1st class tickets from Murcia to Valencia for next week online and i think the price includes free parking at the station.

Apparently i have to "swipe the barcode of each ticket on each train ticket at the carpark ATM machine"

but if there is an outstanding balance i will have to pay this on site prior to entry to the carpark.

All sounds a bit complex to me, does anyone have experience/advice about this?

Abe