I don't think you really need a guide to tour Delhi. However, if you are interested in going for a guided tour, you can check SOTC Holidays. Their Delhi packages - https://www.sotc.in/india-tour-packages/delhi-holidays are quite well planned. I hope this helps :)
I hope you have made your trip. It would be helpful for travellers if you share the travel details:
1.Route
2.Transportation
3.Weather
4.Budget
5.Places to see
6.Tips for travellers etc.
Happy travelling.