Update installation.md

docs/getting-started/installation.md

@@ -4,4 +4,19 @@ Pax is written in pure Python, but depends on C++ code via JAX.
 
 Because JAX installation is different depending on your CUDA version, Haiku does not list JAX as a dependency in requirements.txt.
 
-First, follow these instructions to install JAX with the relevant accelerator support.
+First, follow these instructions to [install](https://github.com/google/jax#installation) JAX with the relevant accelerator support.
+
+After the JAX installation, if you run into into the following problem
+
+```
+Traceback (most recent call last):
+  File "/usr/lib/python3.9/runpy.py", line 188, in _run_module_as_main
+    mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
+  File "/usr/lib/python3.9/runpy.py", line 111, in _get_module_details
+    __import__(pkg_name)
+  File "/home/duser/pax/pax/__init__.py", line 1, in <module>
+    from .version import __version__
+ModuleNotFoundError: No module named 'pax.version'
+```
+
+run `python setup.py sdist`. Then you should be setup.