Welcome to this introductory lesson focused on Array Operations without the use of built-in functions. While JavaScript provides a myriad of built-in methods such as forEach, map, and others to simplify array operations, understanding the concepts behind these key functions significantly improves your ability to solve complex problems and prepares you for scenarios where built-in methods may not exist, or, if they do, may not offer the optimal solution.

Understanding array operations essentially begins with grasping this unique data structure. As straightforward as it might seem, conducting operations on an array without using built-in methods involves organizing and processing the elements in it manually. This may include counting occurrences of specific elements, finding the index of an element, or reversing the array. Careful navigation and precise control over how elements in the array are accessed or manipulated are key to effective array operation.

Grasping the concepts covered in this instruction is critical to succeeding in the practice exercises that follow, so take the time to understand these concepts thoroughly. Remember, we're not just learning algorithms but cultivating a deeper understanding of how we can break down and solve complex problems with relatively simple code. Therefore, get ready and anticipate an exciting, revealing practice session!