"My red bag."
Translation:Tas merah saya.
Word order is incorrect. Should be "Tas saya merah.
Tas saya merah = My bag is red.
Tas merah saya = My red bag.
'saya' functions as a possessive pronoun and is placed after the noun /noun phrase.
tas saya = my bag
tas merah = red bag
tas merah saya = my red bag.