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1. Create the overall (coarser) model
2. Create the smaller (finer) model
3. Open the smaller (finer) model
   1. Specify 'open' boundaries. 
   2. Change forcing to 'time series'
4. Open the larger (coarser) model (see Figure below)
   1. Go to the Nesting toolbox and 'Nesting - 1'
   2. Specify the grid, enc and bnd file of the finer model. 
   3. Generate the 'admin' file by clicking on 'Make Observation Points'.
   4. Define the time step of the observation points
   5. Save all your Delft3D-FLOW files
   6. Run the coarser model
5. Open the smaller (finer) model (see Figure 2)
   1. Go to the Nesting toolbox and 'Nesting - 2'
   2. Specify the history and admin file.
   3. Click on 'Run Nesting'. Boundary conditions can be generated for the “Hydrodynamics” and also “Transport” (e,g, salinity)
      

Example

In this online example Delft Dashboard is used to set up in a few minutes a tidal simulation using a two-level nesting approach. The model includes a coarser model for Southern California, in which an already existing high resolution model for San Diego bay is nested. This possibility is also showed in Tutorial 2: two level nesting.

Figure: With the Nesting toolbox two model are loaded and coupled. The idea is that the Nesting Toolbox will generate observation points in our large (coarser) California model and the output of these observation points is used in the second (finer) model of the San Francisco Bay