The only way is to create a .desktop file related to it and move it to /usr/share/applications/ . Try to refer to other .desktop files. You can set the category as Development in it.
Here is a tutorial in Chinese: https://bbs.deepin.org/zh/post/225323
deepin 
deepin The easy way is to install "alacarte" from the Deepin Store. Youn can then choose your application (bin or appImage) and your icon ...etc. Good luck :-)
deepin The other way as mentionned in psm9012 reply:
Go to the ./local/share/applications and if you find an exemple desktop file copy it and rename to your new application.
Edit the file and modify as this example:
[Desktop Entry]
Comment=3D CAO
Terminal=false
Name=Blender 3.4.0
Exec=/home/laid/Progs/Blender-3.4.0/blender
Type=Application
Icon=/home/laid/Progs/Blender-3.4.0/blender.svg
If you don't find an exemple desktop file than create a new one with Deepin-Editor. Then name must be "AppName.desktop".
Just after creating the file, the new application appears automatically in the system Menu.
Rankings
Popular Events
More
中文 
Hi *,
I am new to Deepin, using V20.8.
I have installed a 3rd party application, which does not enter itself into the start menu of Deepin.
How can I add it manually so that it will show up there?
I would like to add it to the category "Development".
Can someone tell me how to add it there?
Thank you
Daniel