That's a question pretty much equivalent to asking "Where in my car are
the full plans and building specifications hidden?" There are ways of
programming where the "program" that you run is the "source code", the
text that the programmer writes. But pretty well none of those produce
.exe files.
Most .exe files are written in programming languages that are
"compiled". This term has a special meaning for computer people: it
means translating the program from the form that a human can read and
write into a form whereby the computer's processor can run it. This is
not, in general, a reversible process. Many kinds of information that
humans find important or vital in working with a program's source code
are discarded in the process of compilation. This includes all the names
for parts of the program and for items of data within it, all the
explanatory text, and many more things not easily described.
Further, you are in quite the wrong place to be asking this question. To
continue with the car analogy, you have done the equivalent of walking
into a meeting of metallurgists - people who develop metal alloys, not
cars - and asking them about your car, without knowing what make or
model your car is. Nobody is blaming you for this because your naivety
is pretty obvious, but you aren't likely to get the kind of help you
need.
Do you have any experience of computer programming at all? You would
need that to make sense of the source code of any program. If not, you
may wish to learn it, but it is not something that you can pick up in a
few newsgroup postings. It's about as complex, and boring as chartered
accountancy, but much more subdivided. For example, you would expect any
accountant to be able to make some sense of the books of any company.
This is not true with programmers: if accountants were divided into
fifty or so different schools, of widely varying size, that did the
books for different kinds of companies in utterly incompatible ways,
disagreeing over the meanings of terms such as "profit" and "income",
they'd be much more like programmers.
If you want to learn programming, expect to spend money on books about
it, programs for doing it, and some basic training courses. Expect it to
take time: months for basic proficiency, years to get good at it.