Data Structures are super important when you want to store data and access them.
There are lots of heuristic data structures but important ones are:

Basic:
1) Stack
2) Queue

Intermediate:
3) Array
4) Map - HashMap
5) List - LinkedList

Advance:
6) Tree
7) Graph

The way we store them in programs makes the list above and what you have to study is to know which one is faster in which situation.

For example imagine an HTML document, after browser parses the document known as tree:

Store it it's data in some advance tree, then when you for example pass some events that browser has to probe it's nodes to find which node you clicked on.

it's fun when you implement them for example a binary tree has a root and then it has a left and right node:

Node {
   selfData: (Some Data),
   right: Node,
   left: Node
}

above code is pseudo structure of binary code not implementation
Then next nodes might be initialized or be null.

For learning it I suggest getting to know structures I mentioned above in order on paper (skip any part in book saying how to implement it or discussing it's probing time, insertion time and ...)
Then try to implement them by yourself without looking at book, if you fail it's ok then you have to look online for implementations, if there were none search your textbook for implementation.

Then try to study their advantages and disadvantages so you know how much time it takes to insert, remove, search for data inside them.