How the energy in glucose is captured during glycolysis and how does cellular respiration capture additional e?

The first step of respiration is always glycolysis.  Glycolysis is an anaerobic process that converts glucose into pyruvic acid.  Pyruvic acid is used in both aerobic and anaerobic respiration.  Glycolysis produces only a small amount of ATP and NADH.

In glycolysis the energy in glucose is saved in NADH2 and Pyruvic Acid. One glucose molecule gives 2 ATP molecules, 2 NAHD2 molecules and 2 Pyruvic Acid molecules.

The 2 Pyruvic acid molecules goes on to the Krebs cycle and produces 6 more NADH2 molecules , 2 FAHD2 molecules and 2 ATP s. All these NAHD2 and FADH2 molecules go on to the Electron Transmission Chain to produce ATP. One NAHD2 molecule produces 3 ATP molecules and one FADH2 molecule produces 2 ATP molecules in the ETC. That's
10 NADH2 molecules * 3 = 30 ATP,
2 FADH2 * 2                    = 4 ATP
4 original ATPs                = 4 ATP
Total                               = 38 ATPs

Might seem complicated. But slowly go through it again.

And about the last part of your question, i think you're talking about the oxidation of the NADH2 and FADH2 molecules in the ETC. There, NAHDH2 releases an electron which is captured by an agent and that's when the energy in the NADH2 is released as ATP.

Hope this helps and doesn't mess it all up for you