[Idiom] IDIOM EXPLANATION

[MelissaWinslow]

Hi, I would like to know what the following phrases mean...I'm from Romania and I'm not very familiar with english idioms...thank you in advance.....

"I DREW MY LINE ACROSS THE SAND AND SET MY FLAG IN NO MAN'S LAND"

 

[birdeen's call]

draw a line in the sand - Idioms - by the Free Dictionary, Thesaurus and Encyclopedia.
Urban Dictionary: plant a flag

I understand the context is this, and I'm having trouble interpreting the line in the context.

 

[Evil Anagram]

To draw the line across the sand means that you are setting a limit to what you will accept, and it implies that others may join you in adhering to that limit or quit your company. Setting the flag in no man's land is mostly used for the rhyme, but it implies that the speaker is setting out into unexplored/unclaimed territory, though the idiom "no man's land" is usually understood to mean land between two warring parties on a battlefield and may or may not be figurative.