You must flash a custom recovery like TWRP for SM-T211 before you can install a ZIP-based ROM.
A refined KitKat-based ROM that includes several features from newer Samsung devices while maintaining the original feel. custom rom for samsung galaxy tab 3 sm-t211
A highly optimized "de-bloated" version of the stock KitKat firmware, known for stability and better battery life. You must flash a custom recovery like TWRP
One of the early custom ROMs that focused on speed and performance for the GSM (T211) model. custom rom for samsung galaxy tab 3 sm-t211
Install the official Samsung USB Drivers so your computer can recognize the tablet.