For basic instructions on using Noise Reduction, see here:
[DaVinci Resolve 15] 5.8 Fairlight /
Removing General Audio Noise (FairlightFX Noise Reduction)
https://youtu.be/Df6qyn9cwdA
*DaVinci Resolve & ATEM Tutorial Video Collection
https://www.youtube.com/channel/UCY3J0X26AAeqIijVE1kANIw
00:00 Removing Crow Cawing Sounds with DaVinci Resolve FairlightFX’s Noise Reduction
00:13 Audio Before Processing
00:36 Preparation Before Processing
01:00 Starting Noise Reduction
02:30 Comparing Audio Before and After Processing
03:08 Checking the Audio After Processing