How you know multiple characters are one concept I don't know much Chinese but am looking up some basic words to see how it works. For example, the word 天地 translates in English to "world". However, the individual characters translate to this:


天: Day.
地: Ground.


However, Google Translate also translates 天下 as "the world".


天: Day
下: Under


Another example of 2 becoming 1 concept is 种子, "seed":


种: Species
子: Child


That makes sense to translate it into one concept "seed" (unlike the "world" example). But I still don't see how you know when to group characters together into single concepts.

Finally, as one of my first sentences, I am looking at this: 第二道河名叫X, which Google Translate makes into "The second river is called X." The individual components are:


第: First.
二: Two.
道: Road.
河: River.
名: name.
叫: Call.
X: X.


First two road river name call x.

That doesn't make too much sense in direct translation.

The pinyin equivalent divided the Chinese characters into these chunks: 第二, 道, 河, 名叫, X, so those 2-character chunks translate to:


第二: Second
名叫: Name


Second road river Name X.

That makes a bit more sense.

What I would like to better understand is how you learn to group the characters into more complex concepts, and separate them from other concepts (as in 天地 world vs. 天 day and 地 ground). Since Chinese doesn't have spaces, it seems there must be some technique, or perhaps you have to learn the individual pairings/combinations of characters as single "words" or concepts in school at some point, provided with definitions like a dictionary.
Modern Chinese prefer words rather than characters. The former way you translate a Chinese sentence is probably more suitable for ancient Chinese (known as 文言文).

It is not a big problem for a native Chinese speaker to naturally divide those characters into words, however for beginners, it can be hard. But guess what, dividing Chinese characters into chunks is a well-known research direction remaining unsolved in natural language processing and machine translation.

So the answer to your question is: The more combinations you know, the more accurately you can divide. You can hover your cursor on the words in Google Translate, and Google will tell you its (guessed) division scheme.