What subjects are covered at the 35T schoolhouse?

Here is some information to get you started.

A Military Occupational Specialty (MOS) 35T, or Military Intelligence Systems Maintainer/Integrator, keeps the intelligence systems of the United States Army in working order. Their responsibilities include:
Maintaining equipment: Ensuring that intelligence computers, networks, and sensors are in top condition
Configuring systems: Integrating Program of Record and Non-Standard Equipment into Intelligence Architecture
Programming and installing hardware and software: Configuring computer hardware and software for aerial and ground Intelligence Information Services (IISs)
Troubleshooting and repairing: Diagnosing issues with hardware and software, and fixing or planning how to gain or transmit information
Performing pre- and post-flight procedures: Working with aerial intelligence platforms and sensors
Assessing data: Extracting data from communication devices

Some skills that are helpful for this role include:
Interest in math
Proficiency with computer systems, digital networks, and electronic equipment
Strong attention to detail
Enjoyment of problem solving
Basic Combat Training for a 35T is 10 weeks, and Advanced Individual Training is 38 weeks and 4 days at Fort Huachuca, AZ.

https://www.goarmy.com/careers-and-jobs/signal-intelligence/languages-code/35t-mi-systems-integrator