Foreword:
1. Why choose Ubuntu system?
1. It is free and provides long-term system maintenance support; 2. It is a mainstream Linux server distribution;
3. Powerful Shell; 4. Simple and beautiful graphical UI interface; 5. Rich software support;
2. How to contact me?
Three, what should I pay attention to?
1. This tutorial only applies to some UEFI boot computers:
How to check the boot mode of my computer?
Win + R → msinfo32 → 
As shown in the figure BIOS mode: UEFI is UEFI BOOT;
2. It is strongly recommended to check whether the disk has BitLocker before installing dual systems:
Once BitLocker is not released, you will need to enter a 48-digit recovery password every time you select Windows for dual systems.
How to find the BitLocker recovery password for my own disk?
Please contact the manufacturer's customer service for details. You can obtain the recovery password through Microsoft's official website.
How to unlock?
Settings → Device encryption → Decryption (just wait patiently)
As long as there is no lock mark next to the disk, it means the unlocking is successful.
Installation of Ubuntu system:
Step 1 (download Ubuntu and burn):
1. Download Ubuntu 22.04 LTS from the official website
2. Prepare a USB flash drive of 32G or above for burning;
3. Download the burning software (Rufus is recommended);
Why is win32diskimager not recommended? It is possible to reduce the space used by the USB flash drive.
Please follow the steps as shown in the figure to burn, and then open the USB flash drive: as long as the file can be seen, it is considered successful;
Step 2 (Allocate disk space):
Two options are recommended:
Plan 1 is recommended to ensure the stability of user data when reinstalling the system;
Here you can imagine "/" as the C drive of Windows, and "/home" as the D drive of Windows;
Of course Plan 2 can also be adopted;
Remember that the Swap memory space is slightly larger than the real physical memory;
Therefore, we compressed 60.5GB of unallocated space in Disk Manager
Step 3 (Install Ubuntu dual system):
Precautions:
Insert the USB flash drive and start rebooting:
The first step is to press Fn + F2 (taking Lenovo Xiaoxin notebook as an example) to enter BIOS mode:
Select Secure Boot, then Disabled
Finally select Exit Saving Changes;
After restarting, be sure to press Fn + F12 (taking Lenovo Xiaoxin notebook as an example) to enter the driver selection mode;
In the second step, press Fn + F12 (take Lenovo Xiaoxin notebook as an example) to select the driver;
Please select Try or Install Ubuntu;
Step 4 (Preparation for Ubuntu system):
1. The language can be selected from Simplified Chinese or English;
2. Please select the keyboard layout as shown in the picture:
3. It is recommended to use the system default for the middle option, and do not connect to the Internet for the first time;
4. Dual system partition (extremely important):
Please select other options, otherwise you cannot use Win + Ubuntu dual system;
Select the free area and first create a 512MB EFI system partition as the boot item for the Ubuntu system 
Create a swap space (SWAP) of 20480MB (20GB): 
Create a "/" partition with a size of 30720MB (30GB). At this time, select "/" for the "For" option
Then create the remaining space as the "/home" partition. At this time, select "/home" with the "Use for" option. 
Extremely important steps:
Find the Ubuntu efi area file name: nvme0n1p6;
Change the device where the bootloader is installed below to: nvme0n1p6;
At this time, we use Ubuntu boot to start the dual system;
Unplug the USB flash drive and press Enter;
Choose Ubuntu system: 
Wuhu, success! ! !
Uninstallation of Ubuntu system:
Step 1：
Implemented through DiskGenius:
We should delete the Linux boot area (Boot), virtual memory area (Swap), and root directory (/);
Delete and save changes
Step 2：
At this time, careful students will find that when we restart the computer, it will enter Grub mode and enter exit;
So, how to completely delete Ubuntu Boot?
Continue to open DiskGenius:
Open EFI - ubuntu - select all files - delete completely