Hi Artem,
You can look here for the canonical way of using Layouts:
https://github.com/SparkViewEngine/spark/wiki/Master-Layouts
I'm not exactly sure how much of that Fubu actually implements, but in my eyes, the theory is that you should able to put a tag in your Content.spark that says <use master"Application" /> and it should render Application --> Content --> View
Again, I'm not 100% sure Fubu has implemented that, but I would hope it works out the box as long as the views are located by Fubu and presented to Spark correctly.
Hope that helps,
Rob