You can use the characters horizontally or vertically, the order is the same both ways. For art works the vertical presentation is often used.

For the horizontal presentation you read them from left to rigth.

>> I do not know what dialect you use if any? I use Mandarin.

Mandarin is the most widely spoken language in the world. More than one billion of the world's population are Chinese speakers and 21% of people in the world read Chinese while 8.3% read English. 

The Chinese population is already one fifth of the population of the world and is rapidly expanding its presence everywhere.

Modern Standard Chinese is an official language of the United Nations.

Even the Nationalists in Taiwan and the Communists in People's Republic of China agree on that matter: the national language of Chinese is the Mandarin dialect. It is also known as Beijing dialect or "putonghua", literally common language. It becomes the national language "gúoyu" in Taiwan and the Chinese language in Singapore and Malaysia. In Singapore it is one of the four official languages and also use by the diasporas in Indonesia, Russia, Mongolia, Vietnam, Brunei, South Africa, Thailand, Laos, Cambodia, Hong Kong and Mauritius as in many western countries like the USA, UK and Canada where it is already the third spoken language after English and French. A huge Diaspora makes it hard to find a town where there is no Chinese peoples to talk to.

What dialect is used - Mandarin/Cantonese etc?

As China is the most populous country in the world, there are many different dialects spoken throughout the country. In fact there are more than 200 different dialects, some of them so different that they may be considered a different language. You can find one town or city that is unable to understand most of the conversation of a town in the next valley. Standard Chinese, that which in the west is often called Mandarin, is the official national language. Cantonese is a dialect spoken in some of the more southern parts of China, and very different from standard Chinese.