An easy one here really.
When you are leaving somewhere and you are returning later as in ‘I’ll see you later/ I’ll be back in a minute’ etc. you say ‘I go come’.
An example of this would be if I am in the house and Nana is here and I am just popping to the corner ‘shop’ I’ll say ‘Nana, I go come’ and she will know I am popping out for a bit.
You can also say to someone ‘you go and come’ if you want them to return to you.
Nice and simple!