You'll probably get to Sri Lanka by plane to its capital Colombo and the main international airport (Bandaranaike) some 35km north of Colombo.
How to get there depends where you are in time and space. There are plenty of direct flights and mostly indirect flights only have one stop over in one of the main hubs in either India, UAE, or other Asian main platforms. These are some of the carriers flying to Sri Lanka:
After paying and confirming the reservation Surfinn will send you a "How to get there" from the airport to the surf camp. Please note that transfers are always recommended since tourists are usually subject to inflated prices.