Tell me how you want to add missions? Through the JSON object? Or add manually line by line? I'll write it easier:
const buttons = [
{
"name": "Mission 1"
"icon": "iconUrl"
}
]
Result:
fm.button("Mission 1", "iconUrl")
Or
fm.button("Mission 1", "iconUrl")
If you want to use option 1: JSON task generation, then you need to make a button generator. And then already to do scripts of execution.