Replication of "Countercyclical Capital Regulation in a Small Open Economy DSGE Model" of Matija Lozej, Luca Onorante, and Ansgar Rannenberg

General DSGE Modeling Replication Attempts
2

That depends on your background. If you have not worked with DSGE models before, then I would plan with at least 6 months. You will also need proper supervision, i.e. someone to turn to in case you encounter problems. If that is not assured, I would not try to do this.