Nick speaking,
You will find the full instructions on how I magnetised my Necron Tesseract Vault/Obelisk, in a video tutorial I made at the bottom of this post, but as pictures speak a thousand words, here are pictures of all the magnetised areas, so that you can have a quick inspection of my work. I hope this helps and feel free to ask any questions you may have...
How to Magnetise a Necron Obelisk/Tesseract Vault
by IDICBeer | Mar 11, 2016