How do I create a very specific auto generating ground

Hello, so I am verry new to C2 and the whole world, I am a mom who is trying to make a decent games to raise a global isuue in my country.

So i come from an artistic background and I intend to make a runner game with a very specific ground/platform. I have followed some platformer tutorials and i went through the auto runner ( but i am still not able to figure out how i can make the platform appear on the same Y axis but difrent X axis with a same interval of 400 px and the platform being 400, 800 or 1200.

so consider the "x" is my ground and the "o" is empty space which the player has to jump over. (every "x" and every "o" is 400 pixels), so this my goal (to be auto generated): xxxxoxoxxoxoxoxxoxxxoxoxxxoxx etc...

is this possible? can someone help me?

xxxxoxoxxoxoxoxxoxxxoxoxxxoxx.capx

so the file didnt open, i have an older version i guess.

but anw would it be hassle if you explained to me what you did, because i really want to understand the process.