Do you mean that you topped up your cash credit balance with €14?
What do you mean by "activate"?
Do you mean how do you buy a membership with it?
If so then see here:
https://community.48.ie/t5/The-Knowledgebase/All-About-Memberships-and-Payments/ta-p/53105
Memberships include certain allowances for roaming.
Hope this helps.
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