In order to show the item on the /ia menu you must open menu.yml and add the item name to the category you want (in this example I added it to the hoes category):
#permission to allow user to see this category
You can notice there is a special category named all, it has a special property show_all_items which allows you to show all the items you created adding them to this category. If you want to hide some items from this GUI just use hide_items property.
# special tag to hide some items from the GUI