Learn how to enable graphing with swift

I'm a beginner and I'm learning swift from grammar.
You have learned the basic syntax in your textbook.

Currently
apps with Calendar and Graph functions are available. We make it by trial and error.

I would like to ask for your advice
Learn how to achieve graphing with swift as described above.

The following are the points that are currently failing.

To add a graph function, programming from scratch is done from
I'm still in a difficult situation, so I'm going to use the library.

Commonly used libraries:

BEMSimpleLineGraph
PNChart for iOS
CorePlot

I think there are these.

But even the simplest BEMSimpleLineGraph is
I can't even write the letter "gu" in the graph.

Specifically, the following points have failed.

·How are the files used to represent graphs connected and organized?

·In the syntax written in each file (especially ViewController),
　Its meaning is almost incomprehensible with the basic syntax learned.

(I understand the meaning and purpose below, and I have actually set it up, but
　I'm still worried about how to set it up.)

I installed libraries such as BEMSimpleLineGraph on CocoaPods.
I was also able to install it directly without using CocoaPods, but
Both of them seem to be understanding.

Based on the above, what should we do in the future?
Please let me know if you can make an application with Graph function available.

● "If you want to learn with a book"
As far as I've looked up on Amazon, I've found books about graph apps like the one above, and
No library books were found.
Please let me know if there is a textbook that is relatively easy for beginners to understand.

● "If you want to learn through an online blog or commentary on an official website"
If you still don't understand what it says,
Should I re-learn the basic syntax?

● "If you go to school"
It's economically and time-sensitive, but
For example, by pinpointing the above objectives and unclear points,
Is there a school or tutor who can teach it individually?

This is a vague question, but
If you have any questions about effective and efficient learning methods,
I look forward to your kind cooperation.

Below is a reference site

OSiOS http://tech.admax.ninja/10/16/2014/how-to-use-bemsimplelinegraph/