Solve diffusion equation with Neumann boundary conditions and zero initial condition

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The problem I have to solve is the following:

$\frac{\partial p}{\partial t} -c \frac{\partial ^2p}{\partial x^2}=0 \quad \quad (x,t) \in (0,L)\times[0,\infty)$

with

$\frac{\partial p}{\partial x}(x=0,t) =Q \quad \quad t>0$

$\frac{\partial p}{\partial x}(x=L,t) =0 \quad \quad t>0$

$p(x, t=0)=0 \quad \quad x \in (0,L)$

where Q is a constant.

So, there are two different Neumann boundary conditions, and a zero initial condition.

I tried to solve by separation of variables but I'm stuck at this stage, as I don't know how to impose the boundary conditions and the initial condition. I suspect I should use Fourier series but I don't really understand how to do it when the initial condition is 0.

Could someone help me with that? Thank you!