Hello,
This code seems to be doing what you want (let me know if it is not!)
    a = torch.ones(size=(1, 3, 8, 8), dtype=torch.float32) * 2.0
    print(a)
    b = torch.tensor(data=[1, 2, 3], dtype=torch.float32)
    print(b)

    b = b.unsqueeze(dim=0)
    b = b.unsqueeze(dim=2)
    b = b.unsqueeze(dim=3)
    # b passes from a (1 x 3 x 1 x 1) tensor to a (1 x 3 x 8 x 8) tensor
    b = b.expand_as(a)

    # element wise multiplication
    print(a * b)