[TYPO3-extbase-kickstarter] Problem with content elment

[Beatrice Bartoli]

Hi to all,
i'm new of this list, and I'm italian, so please forgive me for my bad 
English :)
I tried to create my own extension with Extension Builder v. 2.4.7 on 
Typo3 v. 4.7. but i had some problem.
I need to create one slideshow to be inserted as content element in a page.
I create 2 object as you can see in screenshot_1 but when i try to add a 
new element in my page the Test extension element appears into the list 
of the record type, as you can see in screenshot _2, and I can add it 
with the right field, but not as content element.
If i try to  insert it as frontend plugin in a content element record 
ther's no field (screenshot_3).
I know that something wrong but I can not figure out what.
Can you help me?

Thank you,
Beatrice Bartoli