First you will need to enable Memcached or Redis. Make note of the "Host" and "Port" details for your chosen caching solution but keep in mind you can return to this section at any time to see these details.
Next you will need to make sure that you have enabled the Memcached or Redis PHP Extensions.
The final step is configuring LiteSpeed Cache to use the Memcached or Redis Object Caches.
Redis is the most popular option and does support multiple sites. Memcached can only be used for one site per account.
To use Redis with multiple sites you will need to specify a "Redis Database ID" that is different for each site.
If the "Memcached Extension" and "Redis Extension" both show "Disabled"
This would indicate that you missed the second step of enabling the Memcached or Redis extension for PHP or that you enabled it for a version other than the version your site is using. Directions on enabling PHP Extensions can be found here.