It seems some sub-modules have the name “model”.
Have a look at this small example, how to index the layers:
class MyModel(nn.Module):
    def __init__(self):
        super(MyModel, self).__init__()
        self.fc1 = nn.Sequential(nn.Linear(10, 10), nn.ReLU())
        
    def forward(self, x):
        return self.fc1(x)

model = MyModel()
print(model)
model.fc1[0] # get linear layer