I understand there have been some offline discussions to discuss some alternative solutions.
However, the API documentation is available in the integrated help in the System administration > API developer documentation topic.
The latest version of the API documentation can also be viewed online here:
https://d3sa-preview.infogixsaas.com/docs/dist/api/index.html
The basic procedure is to create a schedule for the required data flow in the application UI and set its status to Disabled.
Your .NET application would then need to authenticate to obtain an authentication token and use the 'Ad-hoc run of a simple scheduled task' /run-now API to run the scheduled data flow immediately.
See the 'Running a data flow' tutorial here:
https://d3sa-preview.infogixsaas.com/docs/dist/api/index.html#tutorial-simple-scheduled-task-running-data-flow