How to write a stoichiometric matrix for a part of the Pentose phosphate pathway
This is not a particularly well written homework question. I'll try to give some hints based on how I interpret it.

1) The stoichiometric matrix. You have exactly the right idea. I would write the reactions as enzyme names or gene names instead of the EC numbers (e.g. G6PD or G6P dehydrogenase instead of 1.1.1.49). For the reversible reactions, there's no a priori reason to write them in one direction or another, but convention would be to make glucose consumption the positive direction. I would not include "glycolysis" as a separate reaction. I would also consider including cofactors and byproducts in the molecules affected by the reaction (e.g. CO2, NADP+, NADPH, (maybe ADP, ATP, NAD+, NADH also if those come up)).

2) Yes, it's basically what you already have. It's not a particularly great diagram, so you could draw it in a clearer way.

3) I have no idea what this means, but perhaps the next point will help.

4) Primary metabolite is not a super well-defined term, but I think in this context, I would say that the way they're intending the question, they're looking for a "total pathway reaction" that describes the net inputs and outputs of the pathway.

Something like this:

$$
X_1 G6P + X_2 NADP+ \implies X_3 GAP + X_4 FBP + X_5 CO_2 + X_6 NADPH
$$
(G6P=Glucose-6-phosphate, GAP=Glyceraldehyde-3-phosphate, FBP=Fructose-bis-phosphate)

I'll leave it to you to figure out what the X's are or whether I left anything out (since it's a homework assignment after all.)