Leave half the disk unpartitioned and unused, during Windows install. Ubuntu install process will find the empty space and create its own sets of partitions. Ubuntu uses ext4 formats for partitions. Creating partitions using Windows, for Ubuntu will not work.
Keep unallocated space for future use during Windows installation as before.
During Ubuntu installation, choose the "Something Else" when it comes to the type of installation so that you can create your own sets of Ubuntu partition.
I recommend 3 partitions,
/ (also known as root),
/home, and Swap. The size of the first two will depend on your usage needs.
For normal desktop uses 30GB
/ should be sufficient for updates and new software you may want to install. If you want to run web server type of things, you may need more.
For normal desktop use, `/home' takes most of the space. This is where all the users' data files like music, photos, videos, etc. will stay.
Swap can be small, say 2-4GB, unless you want to hibernate your PC, in that case, 6GB.
/home should be formatted ext4. Swap has its own format in the drop down list.
For more on
/home see Home on a different partition
I hope this helps.