create custom field plugin problem

[Nikos Kalogerakis]

Hi
i am new in jira development
and i am trying to learn to build custofield plugin
i need just to fix a simple textbox nothing "crazy"
i did all the steps to this turorial 

https://developer.atlassian.com/jiradev/jira-platform/guides/fields/tutorial-custom-fields-in-jira

and i build it
i add it to jira
to the add-ons page i found my plugin and  its says that all is ok and enebled

but when i am going to the "custom fields" and "add custom field"
to the list with field types i cant see it nowhere

maybe you know any reason that i cant see it in the list ?

thank you