Clockwork Automata are at the intersection of Mechanical Engineering and Computing, although you will also want Psychology if you wish for your creations to have the appearance of a living being rather than pure cold logic.
Mechanical Engineering is a specialism of Engineering, which itself is an application of Physics. Mechanical Engineering is the key discipline required for constructing devices that move and/or can be manipulated, be they precision tools or large vehicles. By necessity, your creations can require a lot of resources to produce, and their efficiency depends on your ability to refine high quality materials with high quality tools. At low levels, you can design and build steam engines, as well as accurate spring-wound clocks. At mid-high levels, you could design your own difference engines, or vehicles that can explore beyond current modern reach. See also Civil Engineering and Materials Engineering.
Computing is the discipline of logic and rules, and notable for being outside of the core trio of Sciences. On it's own, you would be an exceptional accountant, mathematician or policies manager, but works best when you can automate with Mechanical devices. Thus at its cheapest, all you need it a pen, paper, and a willing volunteer to enact the computations. As your level increases, your algorithms become more sophisticated, able to cover more edge cases or make more efficient use of space.
Psychology is the understanding of the human mind, how it works, and how to make it do what you want. It is a specialism of Neurobiology, which is an application of Biology. With some time can figure out what makes a person tick, and then subtly (or overtly) mold them to your needs. You can also imitate an individual, or even manufacture a whole new identity. As your level increases, your ability to control these identities increases further, until you can predict the actions of someone you never directly met better than their own mother could. All this, costing you nothing but time to study your subject.
There are three categories of Scientific Discipline. The Core Sciences (Physics, Chemistry, and Biology) are tje broadest and tend to have few direct uses. Instead each one has a number of Applied Sciences (such as Engineering or Neurobiology) which give direct uses. Each Application also has Specialisms, which are niche uses. When performing Science, your knowledge in the relevant Core, Applied and Specialist disciplines will all apply, although the more general the knowledge is, the less it will affect the result. You can absolutely have higher niche knowledge than its more generally applied parent if you so desire, but that comes at the cost of being inapplicable if you're trying to work in a different niche.
As The Spark, you must pick an Applied or Specialist Discipline as your Focus.