This should work on both galaxy star. S5282 and S5280
Download CWM recovery
Download Super SU
Firstly, boot into odin mode by turn off your phone and wait 10 seconds. This is to ensure your phone has completely switched off.
Hold down power+volume down+home key. A screen will come asking you to continue. Press voume up key to continue.
Open odin as administrator and then click pda and choose recovery file downloaded from attachment. You will have to unzip the odin and recovery. Sometimes Odin wouldnot show files on desktop so make sure recovery is in DRIVE:/ANY NAME/ RECOVERY.TAR
Flash it by clicking start.
The phone will restart.
Switch off phone again. This time boot into recovery by pressing this combination. Hold down power+volume up+home key You may leave power key after you see model number.
Choose flash zip via recovery and choose SuperSU.zip
Restart phone after flashing the zip
YOU ARE ROOTED WITH CUSTOM RECOVERY. ENJOY
Update SuperSU from market if needed
ODIN FLASHABLE FILES FOR SAMSUNG
GIVE PROPER CREDITS IF USING MY RECOVERY AND TAKE PERMISSION BEFORE DOING SO.