“Node” means Because or Due To. While using “Node”, it is usually uses at the end of one sentence follow by another. You can also use “Kara” for the same meaning. Example :
Netsu ga (aru)arimasu. (I have fever)
Gakkō o (yasumu)yasumimasu. (I am taking leave from school)
Combination of the above 2 sentences using “Node”
Netsu ga aru node, gakkō o yasumimasu. (I am taking school leave because I have fever) OR
Netsu ga aru kara, gakkō o yasumimasu.
Here’s another example:
Q : Dōshite rōka ni (tatsu)tatte irun desu ka
Q : Why are you standing in the hallway?
A : Kagi ga nai node / kara, heya ni (Hairu)hairemasen
A : I can’t enter my room because I don’t have a key
Q: Kyō wa mou kaerun desu ka
Q : Going back now
A : Hai, (tsukareru)tsukareta node / kara, hayaku kaette (neru)nemasu
A : Yes, I got to sleep earlier because I am tired.