Intrinsically disordered proteins (IDPs) present challenges to conventional experimental techniques due to their large-scale conformational fluctuations and the transient occurrence of structural elements. This work illustrates computational methods for studying IDPs at various levels of resolution. The included simulation protocol offers a step-by-step guide on how to conduct molecular dynamics (MD) simulations and analyze the results using the Amber and Gromacs packages, employing both all-atom and coarse-grained approaches. This protocol can be easily adapted to study other biomacromolecules, including folded and disordered proteins and peptides. Furthermore, it is discussed in this work how to perform standard molecular modeling operations, such as amino-acid substitutions (mutagenesis) and insertions of residues missing in a protein structure, as well as how to incorporate post-translational modifications into the simulations, such as disulfide bonds, which are often crucial for proteins to attain their physiologically functional structure. In conventional MD studies, disulfide bonds are typically fixed at the preparation step and remain unchanged throughout the simulations, unable to break or reform. Here, in contrast, a dynamic approach is presented. It involves adequate distance restraints applied to the sulfur atoms of selected cysteine residues, allowing disulfide bonds to break and reform during the simulation. The effectiveness of these methodologies is demonstrated by examining a model IDP, the monomeric form of 1-42 amyloid-β (Aβ42), both with and without disulfide bonds, at different levels of resolution. This study not only contributes to our understanding of the role of disulfide bonds but also provides detailed simulation protocols that can serve as a foundation for future investigations. Furthermore, we describe how to perform standard molecular modeling operations, such as amino-acid substitutions (mutagenesis) and insertion of missing residues, and how to incorporate post-translational modifications into the simulations, such as disulfide bonds, which are often crucial for proteins to attain their proper structure. In conventional MD studies, disulfide bonds are typically fixed at the preparation step and remain unchanged throughout the simulations, unable to break or reform. In contrast, we introduce a dynamic approach that mimics bond breaking and reforming by applying additional distance restraints to the sulfur atoms of selected cysteine residues, allowing disulfide bonds to break and reform during the simulation. We demonstrate the effectiveness of these methodologies by examining a model IDP, the monomeric form of 1-42 amyloid-β (Aβ42), both with and without disulfide bonds, at different levels of resolution. This study not only contributes to our understanding of the role of disulfide bonds but also provides detailed simulation protocols that can serve as a foundation for future investigations.