he visto los bloques de otras cuentas y es que en mi cuenta no hay manera de encontrar el bloque llamado "llamar", lo que necesito es saber donde encontarlo ya que en la pestaña de procedimientos no me aparece
my guess you are looking for how to define a custom procedure?
see here MIT App Inventor Procedure Blocks
A very good way to learn App Inventor is to read the free Inventor's Manual here in the AI2 free online eBook App Inventor 2 Book: Create Your Own Android Apps ... the links are at the bottom of the Web page. The book 'teaches' users how to program with AI2 blocks.
There is a free programming course here Course In A Box and the aia files for the projects in the book are here: App Inventor 2 Book: Create Your Own Android Apps
How to do a lot of basic things with App Inventor are described here: How do you...? .
Also do the tutorials Tutorials for MIT App Inventor to learn the basics of App Inventor, then try something and follow the Top 5 Tips: How to learn App Inventor
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
You can't call a procedure that you have not yet created.
So pull out an empty procedure block,
rename it, and
give it parameters.
Then go back and look in the procedures section of the blocks pallette and you will see a call block for that procedure you can pull out.
muchas gracias a ambos me han sido de ayuda