Sudo nano/etc/apt/sources list
Modify the content as follows:
Deb http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/arcade main non - free contrib rpi
Deb - SRC http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/arcade main non - free contrib rpi

Sudo nano/etc/apt/sources list. D/raspi. List
Modify the content as follows:
Deb http://mirrors.tuna.tsinghua.edu.cn/raspberrypi/arcade main UI

Sudo apt to get the update
Perform feedback shows:
Hit: 1 http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian arcade InRelease
Hit: 2 http://mirrors.tuna.tsinghua.edu.cn/raspberrypi arcade InRelease
Ign: 3 https://packagecloud.io/headmelted/codebuilds/raspbian arcade InRelease
Err: 4 https://packagecloud.io/headmelted/codebuilds/raspbian arcade Release
404 Not Found [IP: 54.183.38.243 443]
Hit: 5 https://download.mono-project.com/repo/debian stable - raspbianbuster InRelease
Reading package lists... The Done
E: The repository 'https://packagecloud.io/headmelted/codebuilds/raspbian arcade Release' does not have a Release file.
N: Updating the from to a repository can 't be done by, and is therefore disabled by default.
N: See apt - secure (8) manpage for repository creation and user configuration details.


I was according to the tutorial to do is, for advice