Need Advice.

1.

Identify the smallest, simplest possible part of the problem and start with getting those to work on their own (maybe in separate programs).

2.

Write out an example of the smaller problem by choosing some simple input/data to start with (e.g. small numbers, short arrays, short strings, etc), following through the manual steps one at time. (i.e. starting by solving the problem just for one specific case - not for a general case yet)
For example, this where the lecturer explains a searching algorithm using a small array of numbers - https://www.youtube.com/watch?v=5azaK2cBKGw&t=1430s

3.

Write those steps out on paper in their logical order until you start to see patterns in those steps where some or all of them are essentially repeating the same steps but with different data/numbers/etc

4.

Look for patterns in the steps you've written down, and consider how to apply programming constructs (such as Variables, Arrays, If/Else, For/While, etc.) to express those patterns in a more general way. Remember that if you can get a bit of logic to do something once, then getting it to happen many times is a matter of combining it with a loop.

5.

Write out the generalised 'algorithm' on paper using those programming constructs, then trace it through by-hand to check it matches the same logic you started with.

6.

Translate it into C code and run the program using the same input you used for the hand-written example to test that it gives you the same output. If you're having trouble with the C syntax or compiler errors, you should be able to find loads of examples on Google.

7.

Go through the process again with a more complicated example input; going back through the same process to figure out what the steps should be in a logical order, and looking for the patterns again.