Copy your chosen Custom ROM .zip file and the corresponding OpenGApps .zip package (choose ARM, matching Android version, and "pico" or "nano" variants) to your external microSD card.
Here is a look at the current state of Custom ROMs for the Galaxy Tab 3 SM-T211.
: A classic choice for users wanting a light, AOSP-based experience. Prerequisites for Installation
Back up all local photos, documents, and accounts. Flashing wipes the internal storage completely.
: Hardware acceleration bottlenecks due to missing Marvell chip drivers. Functions like hardware camera encoding or video playback may exhibit bugs. Prerequisites and Desktop Setup