Start by reading the data from Excel: google will show you many ways to do that, but it will depend on the environment in which you are running. For example, a web-based environment cannot use a solution which expects Excel to be installed, and so on.
Find one that fits your needs, and make sure it works into your code: a DataTable is probably a good storage medium here.
Then google for how to save a DataTable to an existing table in SqLite - again, you will find loads of examples.
The idea of "development" is as the word suggests: "The systematic use of scientific and technical knowledge to meet specific objectives or requirements." BusinessDictionary.com[^]
That's not the same thing as "have a quick google and give up if I can't find exactly the right code". You should expect to have to work with multiple operations and change code to fit what you need rather than just "bolt it together" or hope that someone will do your work for you ...