Well, a classic textbook would be "Mass Spectrometry: A Textbook" by J. Gross.
Since you are doing biomolecules, you could also try "Introduction to Mass Spectrometry of Biomolecules: Theory and Principles" by M. Haramija.
In the end, for realistically large systems this will be done by your software, so the theoretical section of your software manual might actually be the best starting place.
Exact quantitative analysis of any analytes by means of mass spectrometry can be carried out, currently, only within the framework of our (own authored theory to me and my co-author as shown in the corresponding references, below) innovative mass spectrometric strochastic dynamic theory and model equations.
Please, consider works [1,3] and the reference section, therein.
[1] Steroids, 181, 2022, 109001
Mass spectrometric stochastic dynamic 3D structural analysis of mixture of steroids in solution – Experimental and theoretical study
B. Ivanova, M. Spiteller
[2] B. Ivanova, M. Spiteller, Stochastic dynamic ultraviolet photofragmentation and high collision energy dissociation mass spectrometric kinetics of triadimenol and sucralose, 2022, in press.
[3] B. Ivanova, M. Spiteller, Exact quantifying of mass spectrometric variable intensity of analyte peaks with respect to experimental conditions of measurements – a stochastic dynamic approach, Analytical Chemistry Letters 12 (2022) 542-561.
Particularly, an examination of peptides via our approach we have performed, as well. Please, consider work [4].
However, please, be informed that the latter contribution shows only application of the basic stochastic dynamic equation. The next two (2) derivative equations within the framework of the same theory and basic model formula are not used in this study.
[4] B. Ivanova, M. Spiteller, Chapter 1. Experimental Mass Spectrometric and Theoretical Treatment of the Effect of Protonation on the 3D Molecular and Electronic Structures of Low Molecular Weight Organics and Metal–Organics of Silver(I) Ion, In Protonation: Properties, Applications and Effects, A. Germogen (Ed.) NOVA Science Publishing, New York, 2019.