Hi Justine,
I would recommend that you get familiar with the Citric acid cycle, including what the intermediates are, where along the cycle the NADHs, CO2s, GTP and FADHs are being produced, and the enzymes involved.
Per Acetyl-CoA that enters the cycle you get 3 NADHs, 1 FADH2 and 1 GTP.
From Alpha-ketoglutarate to Succinyl-CoA: you get 1 NADH, 1 CO2
From Succinyl-CoA to Succinate: you get 1 GTP
From Succinate to Fumarate: you get 1 FADH2
From Fumarate to Malate:(nothing that you need to remember here)
From Malate to Oxaloacetate: you get 1 NADH
Therefore in total you get 3 electron carriers (2 NADHs, 1 FADH2).
A great way to remember them is by NAC NAC GA FA NA.
Hope to helps! :)
-Shin