dual boot - Installing ubuntu 19.10 alongside zorin os 15 with no free space partition

I want to install new ubuntu 19.10 along side my existing zorin os 15 installation.
Below is the file system partition.

As you can see out of the 1TB i have in my HDD, all is given to zorin os now.

But when i try to install ubuntu 19.10 via the usb drive it shows me the option to install along side zorin and also gave me a slider to allocate the space for both os's separately.

I was just curious how this can be done, and if I went on with the slider and then install ubuntu along side zoris will it affect my existing system files in zorin or will it be in a state that is completely lost?

Please help me.

Thank you