Need help setting up Fund I for a minority investment

Have you set up a fund to finance a minority investment?

The context is that my partner and I have been searching as a fundless sponsor for nearly two years.

We now have the opportunity to help close a seed round for a young software company in a high growth market. We would like to structure the transaction as a GP and use our network to fund the transaction rather than self fund. 

We lack understanding on how to do this legally and how much time to expect the process to take.

We also really value this community and wanted perspective from other searchers.

Thanks!