The template parameter contains the pattern that will determine whether it is applied to a new index or not, see the documentation on index templates. The template you have specified here will therefore only apply to an index named apache_elastic_example.
The size of shards and segments matter. With only 1000000 documents I would recommend using a single shard in order to ensure it gets up to a decent size. When you have more data, you would naturally have more than 1 shards, but you should try to keep the average shard size in GB range.