Hello Prerak Sheth,
1> There are examples under SDK package, the "readme.txt" under project described the example in detail.
For example :

2> " API reference " -> The header files for driver describe API information , for example:

3> About how to use SDK on MCUXpresso IDE, you can refer to the DOC " Getting Started with MCUXpresso SDK.pdf"
under SDK package , or "MCUXpresso_IDE_User_Guide.pdf" under MCUXpresso IDE .
Hope it helps,
Have a great day,
TIC
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