Have you done any research on the Internet and on the Anaconda website?
At the anaconda prompt do thefollowing:
(base) $ create env -n py37tf python=3.7
this will create a new environment where python is some version of 3.7
if you want to see first what versions are available, type:
(base) $ conda search python
this will give you a list of all python versions available. If you want to use say 3.7.8 (if it exists, this is only an example) type
(base) $ create env -n py37tf python=3.7.8
When you want to work with specific packages / tools / libraries that are designed for specific versions of python, then it is better to create an environment
separately for them.