I ran the WW3 with restart file! If you run the ww3, you can gain the restart file like restart001.ww3, restart002.ww3, ..., restart00n.ww3.
Than, you have to change the name of the last restart00n.ww3 to restart.ww3. And run the model to restart date.
I mean,
1. If you ran the model 2020.05.01~2020.05.06, you can gain restart005.ww3.
2. Change this file's name to restart.ww3
3. Run the model from 2020.05.06.
Then you can get the result of model what calculate from 2020.05.01