How do you do this?

In thermopylae it is 76-480-999-73-Check, how do you do that? and with that question like can you do like 10 check or in setup chess, can you have different set up materials for different sides or 117 setup material?

you change it in the code I think

so you can just "Change the code"?

By "code" I think he means FEN4. Example:

For # of checks, edit the numbers just after the word lives, according to the order the players move in and which player gets a certain amount of checks.

I will show you : 

You find this part in the fen4 : 

And you click on the digits and modify them with your keyboard. 

This is an example you can do : 

Don't forget to click on "load" otherwise changements will not be implanted. 

ok, thx