Download Minecraft LCE from my forked repo:

https://github.com/CheeseLad/MinecraftConsoles

Launch the game and click on "Achievements" in the main menu. This will open the website in your browser where you'll be prompted to create an account and link it to your player UID.

Once logged in, click on "My Achievements" to view your achievements and their unlock status.

Enter a world and open your inventory to unlock the "Open Inventory" achievement. Refresh the achievements page to see it update in real-time.