how the gallery post is being created?

hello

i am fairly new to wp – and i like the wp-2014 theme.

it looks very good: i love the features: e.g. the gallery-post-example:

https://twentyfourteendemo.wordpress.com/2013/02/13/gallery-post-example/

how the gallery post is being created?

note – each image has got a link – is linked

this is pretty interesting – can you tell me how this is being done – and created?

love to hear from you

greetings