Quick readA fast answer for people who just want to know where the Stake code field is and how to use code maingame without digging through vague or repetitive pages.
If you are here, you probably do not want a lecture. You want the field, the steps and the confirmation that you are not missing something obvious. Fair enough.
This page gives the fast answer and pushes you straight back to the main route.
Useful next step
If this page answered the immediate question, the next sensible move is to open the main guide, check the sign-up steps or compare the related pages before using any code.