First download the script and open files, find the files:
sync_element.lua
And import the your third party resource, then use:
getElementData(element, data, value)
setElementData(element, data, value)
removeElementData(element, data, value)
or you can use export:
exports.custom_data:getElementData(element, data, value)
exports.custom_data:setElementData(element, data, value)
exports.custom_data:removeElementData(element, data, value)