Actually I do not have the experience and also guidelines on this. I did not unplug the HDD for the whole process as i want the HDD as secondary drive.
What i did is search thru internet and there are few methods to disable the secure boot and enable the legacy mode.
Anyway, it was all sorted out. One of my friend helped out.
What i did:
1) Disk management and found out the new Samsung Evo 970 is actually 'Offline' and thus i turned it to 'Online'
2) Change the sequence of boot device and try to boot with SSD
3) It worked and i restarted/shut down for few times to make sure it is good to go
4) Enable secure boot and disable legacy mode and restart/shut down for few times
5) i am pretty sure the SSD is being used for boot because the boot time is shorten ALOT
6) Unplug the HDD and restart/shut down for few times to make sure everything is good by only using SSD
7) Connect back the HDD and formatted it