Installing Ubuntu after Windows is an easy and straightforward process. But installing Windows alongside Ubuntu is a bit tricky and not recommended. But you still have to do it sometimes.
So, here are the steps to install Windows 10 on Ubuntu 16.04 already installed. And you want to run both together.
Step 1: Prepare partition for Windows Installation in Ubuntu 16.04
- To install Windows 10, it is mandatory to have Primary NTFS partition created on Ubuntu for Windows.
- Create Primary NTFS partition for Windows installation using gParted OR Disk Utility command line tools. If you have existing logical/extended partitions in which you want to install windows, then you need to delete that partition and create new Primary Partition.(NOTE: All data in the existing logical/extended partition will be erased. Because you want Windows there.)