To install the Memcached object cache plugin for WordPress and use it to speed up your blog, you can follow these steps:
Install the Memcached object cache plugin from the WordPress plugin repository. You can do this by going to the "Plugins" section of your WordPress dashboard and searching for "Memcached". Alternatively, you can download the plugin from the WordPress plugin repository and install it manually by uploading the plugin files to your WordPress installation.
After installing the plugin, you will need to configure it by going to the "Settings" section of your WordPress dashboard and clicking on the "Memcached" option.
In the Memcached plugin settings, you will need to enter the hostname and port number of your Memcached server. You will also need to specify the number of objects to store in the cache and the expiration time for the objects.
Save the plugin settings and test your WordPress installation to make sure that the plugin is working as expected. You should see an improvement in the performance of your blog after installing and configuring the Memcached object cache plugin.
Keep in mind that the Memcached object cache plugin is just one of many different caching plugins available for WordPress. There are many other caching plugins that you can use to improve the performance of your blog, and you may want to try several different plugins to find the one that works best for your specific needs.
For more information about how to install and configure the Memcached object cache plugin for WordPress, you can consult the plugin documentation or seek assistance from a qualified WordPress developer.