Unable to install for Drupal 8

Problem/Motivation

I tried to install the module with composer, but it failed with errors:

Your requirements could not be resolved to an installable set of packages.

Problem 1
- Root composer.json requires drupal/devel_php ^1.5 -> satisfiable by drupal/devel_php[1.5.0, 1.x-dev].
- drupal/devel_php[1.5.0, ..., 1.x-dev] require drupal/core ^9.2 || ^10 -> found drupal/core[9.2.0-alpha1, ..., 9.5.x-dev, 10.0.0-alpha1, ..., 10.1.x-dev] but the package is fixed to 8.9.14 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command.

Steps to reproduce

Trying to install on Drupal 8 system.

Proposed resolution

This might be "srupid user problem", I'm not good in using composer. But if it is about how to use composer, then 1-2 lines of documentation about how to install on Drupal 8 could be enough to solve this.

Remaining tasks

User interface changes

API changes

Data model changes