So conventional seasoning doesn't work here ?
Yes and no. If you wear off the porcelain coating or damage the surface, you'll have to season it or at least keep damaged sections oiled. Otherwise, you won't, and you'd just oil during a cook like normally.
Only raw cast iron "lasts forever" because there's no porcelain coating to ruin. The GBS system hasn't been around long enough to know if it only lasts a few years or many.