YAML spec file '/Users/..../opera_cslc_env.yml' not found. Aborting

I’m new to Anaconda and am having trouble installing all the code necessary for analyzing SAR data on Mac Studio with Sonoma 14.5.
I downloaded Anaconda from Installation Success | Anaconda - apparently successfully.
Then I executed the following commands directed by a SAR tutorial website from December, 2024.

conda create -n opera_cslc python=3.12 --yes
conda activate opera_cslc
conda install -c conda-forge mamba --yes
mamba env update -p ${CONDA_PREFIX} --file “opera_cslc_env.yml”

The final mamba command failed at the end with the message:
YAML spec file ‘/Users/davidnelson/opera_cslc_env.yml’ not found. Aborting.

Any idea what I can do to complete the installation?