Understanding water models?
I can explain some of this, and actually some of it is explained on the Wikipedia page you referenced. 

Most water models represent the oxygen using a Lennard-Jones potential, which encapsulates the repulsive interaction that stops the molecules getting too close (this is physically because the electron shells don't want to overlap each other) and a long-range attraction due to Van der Waals forces. The Lennard-Jones potential can be parameterized in several ways, two of which are:
$$
v_{\text{LJ}}(r) 
= 4\epsilon \left[ \left(\frac{\sigma}{r}\right)^{12} - 
\left(\frac{\sigma}{r}\right)^{6} \right]
= 
\frac{A}{r^{12}} - \frac{B}{r^6}
$$
The first of these appears in your force field specification file.
The $\epsilon$ parameter is actually given in Kelvin, which is $\epsilon/k_{\text{B}}$, where $k_{\text{B}}$ is Boltzmann's constant.
Hence the note "this is K".
This may seem an odd choice, but there are some historical reasons.
However, you'll see on the same line,
in a comment for the user, 
that this number is translated into SI units and also into old-time cgs units of kcal/mol.
The $\sigma$ parameter is also given in your file, in old-style Angstroms.
Just to be clear, this is the interaction between oxygen atoms,
hence it is described as the O-O Lennard-Jones term.

The second form appears on the Wikipedia page. The values of $A$ and $B$ appear in the table, in old-time units. If you do the necessary multiplications
you can check that (to within a few significant figures, anyway),
$4\epsilon\sigma^{12}$ and $4\epsilon\sigma^{6}$ do indeed agree with the
tabulated $A$ and $B$, taking $\epsilon$ in kcal/mol and $\sigma$ in Angstroms,
for the SPC/E model.

There are some redundant entries in your file: BEND and BOND. For a molecule like this,
one could allow the OH bonds to vibrate, and the HOH bond angle to vary,
and these terms would need some force constants and equilibrium bond lengths and
angles.
But SPC/E is a rigid model: the bond lengths and angles are fixed,
so it looks like the force constants ($K$) have been set to zero.

One might imagine that the H atoms deserve also to be represented as Lennard-Jones atoms,
but they are quite small, and in this model this aspect is neglected.
Hence we see that $\epsilon$ is zero for the H-O and H-H interactions.

So then, all that is needed to complete the model is the charge distribution,
and it looks like you've identified the three charges,
one on each atom,
characterizing SPC/E.

This isn't the most sophisticated model,
as you can see if you scroll down that page.

For more details concerning the input file,
I would hope that your software package and/or exercise instructions,
give enough information.
Hope this helps at least to understand the correspondence between the
numbers in your file,
and the numbers on the Wikipedia page.