Look over install/usage instructions

In the README there are several ways to install the tools described, and some are untested or described as deprecated. Decide on the best way (or ways?) and describe them. Preferrably also make automated test to verify the instructions (and/or automate all steps using a script).

Also, is asdf a useful tool to support? https://github.com/asdf-vm/asdf

Start with the installation and usage instructions in the README, then review the listed methods for current support and deprecation status. Check whether asdf is relevant using the linked asdf project, and determine whether instruction verification or a script is practical. Done means the README clearly describes the recommended installation path or paths and resolves the asdf question.

Written by the indexing model from the issue text.