How to install windows 10 and ubuntu on ssd without unplugging the hdd

Currently in my laptop I have Windows and Ubuntu dual booted on a 1TB hard drive. Now I have bought an samsung 850 evo 250GB M.2 SSD where I want to do the same thing , ubuntu and windows 120GB each.All of the tutorials I found tells to discoect the hdd first. But , I don't want to do that because of warrenty purposes.

So ,how would I achieve that , I mean after plugging a clean SSD , how would I create partions in the ssd ,and how would I install OSes on that ? Thank you