In Odin, click the (or PDA) button and select your twrp-3.0.2-1-smt560.tar file.
You forgot to enable "OEM Unlock" in Developer Options before flashing. Fix: Reboot to stock ROM (you may need to re-flash stock firmware via Odin first), enable OEM Unlock, wait 7 days (Samsung’s RMM lock on older devices), then reflash TWRP. twrp3021smt560tar full
: Go to Settings > About Tablet and tap "Build Number" seven times. In Odin, click the (or PDA) button and select your twrp-3
.tar (Odin-flashable package for Samsung devices) enable OEM Unlock