First contact a local amateur radio operator, or amateur radio club and ask for help. Radio amateurs are enthusiastic about their hobby and most of them will be willing to help you participate in the JOTA.
Most Scout Associations have appointed a National JOTA Organizer (NJO) who can bring you into contact with a radio amateur. Otherwise, the national amateur radio organization in your country will be able to give you the name and address of a radio amateur in your area.
The radio operator may suggest that the Scouts visit his station during the JOTA, or that he brings his equipment to your local headquarters, or campsite. Often JOTA radio stations have been set up in unusual locations such as at the top of a mountain or on a boat.
Radio amateurs have obtained a licence for their radio transmissions from the authorities in their country. They passed a technical examination to obtain this licence. License conditions vary from country to country. In some, Scouts may speak over the air themselves; in others, special permission can be obtained for the Scouts to speak over the radio themselves during the JOTA weekend.
Where Scouts are not allowed to speak over the air, the licensed operator will have to make the contacts. If the operator is not a scout or leader, he will need a special briefing on Scouting and your group. The operator should be able to talk about Scouting in your local area and be able to have friendly and informative exchanges on behalf of the Scouts present. The Scouts can help to brief the operator and tell him the sort of things they would like to find out from other Scouts.