You do not need to take any action to activate your ISIC card. The process is fully automated by Expatrio. All you need to do is activate your TK Health Insurance. You can find more details on the TK Health Insurance activation process here.
After you activate your TK Health Insurance your data will be automatically forwarded to ISIC so that they can create a card for you. It normally takes around 1-2 weeks after TK Health Insurance activation for you to receive the ISIC card.