can you help me about language ?

Another means one more of the same - one girl walked by, then another girl walked by

Other means a different one of the same or similar thing - not that girl, the other girl

Each other means all of the things, same or different, together - the four girls were all friends with each other

One another is similar to each other and means each thing in the group - the books were stacked on top of one another

Other = something different.

Example: "My favorite color is blue, but other people prefer other colors."

Another = an + other

Example: "My favorite color is blue, but you prefer another color."

Each other = double object of a reflexive verb.

Example: "The two men looked at each other" = "Each of the two men looked at the other man"

Example: "The two trains crashed into each other."

One another = plural object of a reflexive verb.

Example: "The five men looked at one another" = "Each of the five men looked at the other four men"