Japanese doesn't use spaces like English. If this sentence were in Japanese, then it would like like this: thisishowjapanesewritesentencesandma
ybeitconfusesyoubutifyouknowthelanguag
ethenyoucanpickoutthewords.
(Notice I did a line break within the word, no hyphen, just like in Japanese.)
They have commas, periods, and quotation marks (looks different than ours). Traditionally no question marks or exclamation points but a lot of people use it these days. Foreign words may be separated by a dot floating in the middle.
I'm guessing you just started learning Japanese? If that's the case, you can guess at what's a word by taking chunks of kanji and throwing it in the dictionary. Probably 2 kanji together is one word but not always. Could be 3 or 4 sometimes. Particles, learn them and you can figure out where some of the words are. Another tool is a web browser within a web browser. If you go to this site and view web pages with it, then you can put your mouse over kanji and it will give you the reading and translation, which is really useful!
http://www.rikai.com/
But first I suggest you learn more basic stuff, perhaps sentences with little to no kanji in them.