The national PEPR SupraFusion program includes the SF-Plant project, led by CEA-IRFM, which studies the feasibility of a high-field fusion reactor and addresses the challenges of electrogenic machines. A thesis has been launched to study the cryo-magnetic system and proposes an integrated design of the toroidal magnet and the central solenoid, focusing on structural aspects. The thesis is divided into three main parts: improving magnet design tools for high fields and using high-temperature superconductors (HTS), leading to a preliminary design and identification of blocking points. Detailed studies will then be conducted on these blocking points, with particular emphasis on the mechanics of these complex structures. Finally, the doctoral student will integrate the results of the detailed studies into the overall design of the plant and optimize the design tools, simplifying complex behaviors to allow optimization loops.