How can I code this system of differential equations?

I'm trying to punch in my system of equations, but I'm having a really rough time making sense of Matlab. I'll explain the system here:

I'm currently working on a project wherein I have to code a system of differential equations. My system is based on plants. I'm determining that L(t) is going to be the length of the plant, and dL/dt is the rate at which the plant grows over time. Here's what the equation (thus far) looks like:

dL/dt = aL(L initial - L final)

My professor suggested some alterations, and said that this would be a bit better:

L’=a(S+W+N)(1-1/k)

Where S,W,N stand for sun, water, and nutrients respectively and k is the max height of the plant. He then suggested I could figure out responsible equations for derivative of S, W, and N. He imagined maybe something like this but I’m not sure:

N’= aL

W’=E+bL+cR

S’=dL where d is constant

Where L is the length of the plant, E is the evaporation and R is the water that comes in from rain.

Then R’= a step function that is 0 most of the time and K and certain time intervals that you determine. A similar structure can be used for S’ I think.

Any help is greatly appreciated - I'm just having trouble figuring out how I can punch it into matlab.

Here's what I have so far: I added random numbers for the time being to act as filler.

function dLdt = first_order (L,t)
    a = 1;
    L0 = 3; %inches
    Lf = 6; %inches
    S = 6; % hours of sunlight
    W = 0.1; % liters of water
    N = 1; % nutrients
    k = 1;
    
    L'= a(S+W+N)*(1-1/k);
    dLdt = aL(L0-Lf)
end