Why are you even here? You're not fooling anybody into thinking you have any knowledge of this subject.
Quickly learning C
Charles Richardson
Jeremiah Myers
stfu nigger
Kayden Sanchez
Congrats on the job.
With 4-5 years of experience in C++ your are very well setup for it. The jump to C has less to do with learning the language it self, but in letting go of classic paradigms and adopting into what the code base does. There is always the adaption phase when getting into the job. You will read the previous code base and try to integrate into that long before you start actually writing shit.
C code bases are WAY more diverse than anything modern, because there is less of a framework to begin with. Some opt to replace OO with a whole of entity component system. Understanding that ECS then becomes way more important and all of that is largely bound to the code base you will be working on.
Don't sweat it, read up some articles of going from C++ to C and the rest will mostly depend on how the code base is layed out.
Embrace not having to layout everything in objects with complex inheritance.
On a personal note: the biggest C obstacle for me was understanding how to properly work strings, there is so much to do wrong.