How to go to Changi Airport from near KSL CityMall by MRT?

please help how can i reach Changi Airport by MRT from area near KSL CityMall.
Taxi is asking RM 350 for one-way to Changi airport. I cannot afford such fare.
Im very new in JB that is why i really need detailed instructions on each rides i will take to reach Changi Airport.
thank you

ride SBS bus from Larkin Terminal JB going to Woodlands LRT Station in Singapore

Woodlands station to City hall station then transfer to Green line Lrt going to Tanah Merah Station then transfer again another connecting lrt going straight to Changi Station.