You can create resource with "+ Create New Resource" button which is located in the panel to the right.
If this setting is enabled, then every time you use resource, it will be replaced with same value. For example, if you are reading from file with 'Reuse Resource' enabled, then same line will be used during all thread lifetime. You need to disable this setting to take new line.
By default script will stop after resource is finished. You can use this option to complete not the entire script, but only the thread.