If you have a driver's license issued abroad, you just need to go to "Regitra" and exchange it for a Lithuanian driver's license if your country has signed a convention with Lithuania on driver's license exchange. Check your eligibility with the Lithuanian embassy in your home country. Exchange is possible provided that you are staying in Lithuania for more than 6 months.
If you travel to Lithuania for a short period of time, you don't need to do anything. Driver's license from other countries are valid and accepted in the country.