For the purpose of this test, it is assumed that Xposed is already installed and working.
But, for clarity, the steps required are:
- Ensure you have a boot image flashed with dm-verity disabled! Otherwise, Xposed installation will cause the device to not boot! Generally any rooted image will have this done.
- Install TWRP
- Flash the xposed zip matching your OS version (7.1.1 64-bit http://dl-xda.xposed.info/framework/sdk25/arm64/xposed-v88.1-sdk25-arm64.zip)
- Install XposedInstaller (required) and verify it works
That's it. Root is not strictly required as this patches the system when installed.