Custom ROMs come blank without Google services. Download the ARM, Android 7.0, Pico or Nano package from OpenGApps. Step-by-Step Installation Guide Step 1: Enable Developer Options and OEM Unlock Open Settings on your tablet.
OmniRom is known for being a "lighter" alternative to CyanogenMod/LineageOS. The Android 7.1.1 port for the SM-T285 aims to deliver a minimalist, clean experience. Sm T285 Custom Rom Android 7