when should resign ina game ?

at what point when you are losing in points should really give up and try another game ? at 12 points behind at 15 when is the the point spread to great to over come if you are just a beginner player under 200 --also should you resign when your opponent is over 100 points ahead of you in the score scale ?

You resign when there is no hope of drawing or winning a game.
That has not much to do with the material balance.
'No one ever won a game by resigning.' - Tartakower
Here is a game where Reshevsky lost his queen against Fischer, but played on.
https://www.chessgames.com/perl/chessgame?gid=1008376

Look for chances to draw (e.g. Stalemate or 3 fold repetition) instead of focusing on how much material you are down by. At the beginner level, your opponent might lack the technique to secure a victory.

3 fold repetition -- what is that exactly ??? do you end in a stalemate after playing the same move three times??????????

3 fold repetition is when the same position repeats itself 3 times during the course of a game.

thanks for the information it was helpful