First possibility: From the airport take the internal bus no. 5 (3 floor in the airport terminal) to bus no. 475 to Tel Aviv central bus station. From there take Bus No. 70 which stops at Shaul Hamelech / Leonardo Da Vinci Str. every 10-15 minutes.
Second possibility - From the airport take the train to Azrieli Train Station (I'ts called also "Hashalon Station"). From there take Bus No. 56 which stops in front of the Kibbutz Movement (13 Leonardo da Vinci St.)
Our office is open from Sunday to Thursday, 8:30 to 14:30, so, if you arrive in the afternoon or in the weekends (Friday and Saturday) and will have to spend the night in Tel Aviv, take the same bus to Tel Aviv and book in to a hostel. Then come to our office the following morning or Sunday morning. Remember that our weekend is Friday and Saturday and that Sunday is a regular weekday with regular office hours.
Please note it's only a friendly recommendation, and we cannot assume any responsibility regarding this or any accommodations.
In the summer, we recommend to book in advance.