This Navajo word means “and then,” or simply “then.”
For example, someone tells you “take out the trash, and then go feed the horses.”
Or, you’re getting directions in Navajo: “Take the first left and then when you get to the big water tank go right and then keep going until…” and so on and so forth.
This is completely acceptable usage of the word, even if it results in what seems like a run-on sentence.
In Navajo, sentences don’t necessarily end with a period, but can always continue with words like “dóó” and “ndi”.