i want to ask that, can i skip the registration of digital ocean,and can i continue my training without registration.
Yes, you can skip digital ocean and instead you can use Ubuntu server using a VMware software. The installation of ubuntu takes almost 1gb and VMware software of 72mb.Ubuntu is better than digital ocean since you get a lot of trouble shooting problems like that your debitcard doesnt support the billing process and digital ocean is only a trial version which only works for a meagre time and so you can use ubuntu with free cost and at any time.
but sir Ubuntu is a kind of a window. so have to install the new window
Yes, of course, you can