Read a .xls or .xlsx file and insert it into a SQLite database

What is the simplest way to read a .xls or .xlsx (not .csv) and insert it into a database in Android. I've been reading many guides and examples but they are just too complex for me since I'm only starting to develop an Android App.

I want to know the most easiest and understandable way to insert data in database using .xls columns. Like for example I loop a .xls with 3 columns and insert each row into a query like db.execSQL(INSERT INTO blah blah (column1 in db, column2 in db, column3 in db) VALUES (row1, row2, row3))

I prefer links that have comments in them step by step for real beginners or better answers that have step by step comments.

I also want the .xlsx or .xls file to be read from the ExternalStorageDirectory.

Can anybody help me out? Thank you!