If you're getting errors which include a yellow background when you try and place roads, districts etc or the terrain simply won't load chances are that you're running the game on hardware that is below minimum spec. Please run DxDiag (https://www.intel.com/content/www/us/en/support/articles/000022556/graphics.html), save it (it makes it easier to read) and then open it. Compare what you see to the minimum specs and you'll most likely find that the dedicated memory on your hardware (under display devices) is less than what the game requires. If you're using an Intel integrated graphics device please know that the game doesn't support these and the game will never work properly. Colossal Order gave a recommendation to request a refund and you can read it here (the entire thread is worth reading!)
If this is the case you'll either need to upgrade your hardware or request a refund as the game will never work properly on your computer.