Godbolt [0] is an invaluable resource. But simply setting up tasks to yourself and completing them may be the best course of action. Then you'll find whatever resource you need for a concrete objective.
For example, if you have a week, I'd suggest to start "in the middle", and move up and down according to your tastes.
- Write a hello world program in C, compile it and run it. Try to compile it statically and understand the difference.
- Ask the compiler to produce an assembly file. Try to build the executable from that assembly.
- Try to write a hello world in assembly language by yourself, compile and run it.
- Write a program in assembly that prints fibonacci, or prime numbers.
- Now, forget about assembly and move upwards. Download python source code, compile it, and run a python hello world with that interpreter.
- Look at the Python source code, which is written in C, and try to follow what happens when you run your hello world.
- Try to change the "print" function of the python interpreter so that it prints your string backwards.
Depending on your experience, you may need more than a week (5 days) to complete all these steps. But that's OK! In a few months you can find a new spare week and continue your work.