Where Dropout should be inserted?

I want to use Dropout as a regularization.

I have ResNet Encoder and GAP Classifier.
If I add one Dropout(), where should I insert this?

class Classifier(nn.Module):
    def __init__(self):
        super(Classifier, self).__init__()
        self.conv = nn.Conv2d(64, kernel_size=1)
        self.avgpool = nn.AvgPool2d(8)

    def forward(self, x):
        x = self.conv(x)
        x = self.avgpool(x)
        x = x.view(x.size(0), -1)
        return x