Upgrade to Windwos 10 form DVD on a Precision Tower 3620

We bought a Precision Tower 3620 with Windows 7 Pro 64 that runs ok, now we want upgrade to Windows 10 using the DVD included in the box, but after booted from DVD the menu path is:

Chose the language -> (italian) -> Keyboard layout -> (italian)

-> Options:
1) Continue (exit and continue with Windows 7)
2) Problem resolution
3) Turn off PC

How to proceed to install Windows 10 ?

Thanks,
ALex.