Out sample forcasting using monte carlo simulation

[evinya]

hello everyone, i am very new to simulations but i have this task to complete for my research..

1.Estimate a model
2. Generate 37 random errors
3.calculate 37 forcast #'s
4.Subtract from real #'s to get errors(for-cast)
5Calculate MSE of 37
6.Repeat R times
7.Average over R times

i just need someone to help me with a basic approach to this monte carlo simulation...I have seen some codes on this forum but didnt make sense to me
Thanks