installation not working !!!

The installation guide is in the readme.txt file but as you will see it’s pretty straightforward, at least it should be.
We’ve noticed that on some WP setups the installation fails because of a lack of resources (memory, processing time). It does install a full MyBB in the back-end.
Best would be to activate WP debug in the wp-config.php file (look for WP-DEBUG and set it to true). Then try to reinstall and see what errors pop up.