How to import an existing ubuntu into wsl

Does anyone know how to import an existing Ubuntu system into a windows subsystem?

Ubuntu system info:

OS: Ubuntu 18.04.5 LTS x86_64Host: 20H5006TGE ThinkPad E570Kernel: 5.4.0-56-generic CPU: Intel i5-7200U (4) @ 3.100GHz GPU: Intel HD Graphics 620 Memory: 6844MiB / 15916MiB

Windows system info:

Edition: Windows 10 ProVersion 1909

I want to run it on wsl2.

Thanks in advance