how to install windows 7 on my dell vostro 3470 in UEFI boot

@redxps630 

Legacy boot and CSM is no longer supported.

The basic answer is you cannot do that EVER.

Windows 7 DOES NOT SUPPORT UEFI GPT Booting.

So there is no such thing as legacy boot on internal storage.

https://www.dell.com/support/article/en-us/sln309720

legacy is gone as well as 32 bit driver support

If you want to continue you will need to find a model like 7020 7040 etc that supports 32 bit legacy os.

"Windows 7 was designed 11 years ago. For Windows 7 to run on any modern silicon, device drivers
and firmware need to emulate Windows 7's expectations for interrupt processing, bus support, and power states
which is challenging for Wi-Fi, graphics, security, and more,"
"OEM's make customizations to legacy device drivers, services, and firmware settings, customers
have been told 7 is EOL. There will not be Windows 7 ongoing servicing."
There is no more support for Windows 7 and Windows 8.1 on the newest PCs past Intel's Skylake processors
ALL next-generation processors will require the "latest Windows platform and no longer have 32 bit support or
Compatability Support Module (CSM)." All will be CLASS 3 UEFI.

GAME OVER MSDOS

@redxps630 

You cannot boot windows 7 or 8.

https://www.dell.com/support/kbdoc/en-us/000151899/

All newer systems past 6th gen skylake from ALL vendors and ALL processor manufacturers only support UEFI have NO CSM and NO Legacy MBR booting. Any suggestion that you can dual boot is nonsense.

its

Windows 10 64-bit
Windows 10 64-bit Professional
Windows 10 64-bit National Academic (STF)
Ubuntu 16.04 LTS (64-bit
ONLY.

This is mandated by INTEL ATI NVIDIA MICROSOFT ETC.
So any talk of dual booting is complete nonsense.
ALL Newer Dell systems will not boot the OS in legacy mode from an internal drive. This is step toward Intel's goal of removing legacy support altogether --Microsoft stopped this past 6th gen skylake in 2016, CSM is completely gone DEC 2020.

INTEL, AMD, NVIDIA, etc are going along with microsoft and no longer supporting anything Legacy.

https://www.amd.com/en/support/kb/faq/gpu-630

https://www.nvidia.com/page/legacy.html

https://www.intel.com/content/www/us/en/support/products/97504/graphics-drivers/legacy-graphics.html

https://nvidia.custhelp.com/app/answers/detail/a_id/4604/related/1/session/