Get started with the CLI
Download the application from the Application Page. After installation the 3D2P application should be available in your PATH variable and therefore callable from any command prompt. Open a command prompt and enter 3d2p -h. The CLI should show you all available commands. Enter 3d2p --version to show the installed version of the CLI.
You are able to start the 3MF viewer either by entering 3d2p into the command prompt or with the created start menu entry on Windows. If you are using the command prompt to open the viewer, you are able to pass a 3MF file as an argument to open it. Or just associate the .3mf file ending with the 3D2P application. This way a simple double click on any 3MF file will open it in 3D2P.
As you may have seen the CLI ships commands to create project files. These project files hold information about what a resulting 3MF file should contain, if you package the project. But using the CLI for this is tedious. So head over to the next section to see how you can use the Visual Studio Code extension to create and manage a 3D2P file.
Visual Studio Code
If you don't know Visual Studio Code, it is a free and open source text editor which is highly extensible and great for many Use Cases.
Install the extension
To install the extension, go to the extension tab in Visual Studio Code and search for 3D2P and hit install.
Create a 3D2P file
Open a folder - ideally it already contains all your project files like images, STLs and a readme. Inside your folder press Ctrl+Shift+P to open the command bar in Visual Studio Code. Enter 3D2P: Initialize 3D Print Project (first few letters should be enough to find it). Press enter and follow the prompts. On the thumbnail and readme prompt just hit enter to open a file chooser.
The easiest way to add STLs to your 3D2P file is by open them directly in Visual Studio Code. Right-Click a STL and select 3D2P: Open STL. From here just press addSTLToProject and select the current STL status.
After adding the STL to your project, your are able to change the Status and Color of the STL directly in the viewer. Furthermore you are able to add Notes to your STL by double clicking a position on your model. Initially the note is empty and is only a Mark. Press edit and use Markdown to add some information.
Package the project
If you are happy with your project, you are ready to create the 3MF file out of the 3D2P file. Press Ctrl+Shift+P again and enter 3D2P: Create 3MF. Press enter and wait a bit. The created 3MF file will be saved into the root of your opened folder in Visual Studio Code. Right-Click it and pree 3D2P: Open 3MF to show it in the installed application.