So I have been working for 3 years and have never filed because I honestly just didn’t know what to do but this year I’m trying to settle all of my taxation’s but i dint jnow where to s

You can start by reviewing the requirements for filing a tax return, to see if your income level required a tax return for each year. 

The requirements to file in 2019 are at this link if you can't be claimed as a dependent by another person, and at this link if you can be claimed as dependent on another person'r tax return.  Even if your income levels don't require you to file, some situations listed at this link still require you to file.

The requirements for years prior to 2019 are similar, you can refer to IRS Publication 501 for each year to get the exact requirements.

Note that even if you aren't required to file a tax return, you may want to do so if you had income tax withheld and can get a refund.

Once you know that you are required to file you can file the tax years before 2019 using the Download/CD version of TurboTax for that tax year. Previous year's TurboTax versions are available from TurboTax at this link.

For 2019, you can use either the Download/CD version, or TurboTax Online.

If you file the "oldest" year first, TurboTax will automatically pick up your personal information when you start the tax return for the next year.