Solving heat diffusion equation

Hello everyone ,

I need to solve the heat diffusion equation as follows: ρCp(∂T/∂t)=∇(λ∇Τ)+Q --> ρCp(∂T/∂t)-λ(∇^2)Τ=Q

I would appreciate if someone could provide me a code to solve it? I am a beginner and hardly know how to make it.

T is the temperature (K) , ρ is the water density (kg/m3), Cp is the specific heat (J/kg/k), λ is the thermal conductivity of the water (W/m/K), and Q (W/m3) is the external heat term. The external heat is dependant on the laser irradiance W (W/m2) and the absorption coefficient of the absorbant : μα (1/m).

Thank you in advance.

Best, Sofia