I am a beginner and I do not know How to solve this Error

Solving environment: \
Found conflicts! Looking for incompatible packages.
This can take several minutes. Press CTRL-C to abort.
Building graph of deps: 0%| | 0/5 [00:00 python[version='2.7.*|3.5.*|3.6.*|>=2.7,<2.8.0a0|>=3.5,<3.6.0a0|>=3.6,<3.7.0a0|>=3.8,<3.9.0a0|>=3.7,<3.8.0a0']

Your python: python=3.9

If python is on the left-most side of the chain, that's the version you've asked for.
When python appears to the right, that indicates that the thing on the left is somehow
not available for the python version you are constrained to. Note that conda will not
change your python version to a different minor version unless you explicitly specify
that.

Start by reproducing the reported environment-resolution failure with Python 3.9 and inspect the fbprophet compatibility constraints shown in the error. Done means identifying and documenting a compatible Python and package combination, or confirming the installation limitation.

Written by the indexing model from the issue text.