[Help] Creating a helper creature

Hey there, modders!

I have been working on a little mod as of late, but I got stuck when trying to create a mob and don't know how to proceed.

A little context is needed, I 'spose: the little mob is supposed to be a helper that aids the player with certain tasks, like gathering materials (think of Thaumcraft's golems)...and this is exactly the part I got stuck at.

I need the mob to do certain things, and I am stumped as to how to do it (or, well, rather, I already tried doing it with procedures, using stuff like templates and such, but I couldn't get it to work properly), which is exactly why I went straight to the forums so, if anyone wants to lend a hand, that'd be appreciated! (Let it be known that, while I can't code, I am willing to use provided custom code...just kind of explain what to do and we're golden!). 

The mob has an inventory with two slots, one functional one and one for storage, and should essentially do a few things:

1. Check one of its inventory slots (the functional one) to see if a block is in it;
2. If it is, find that same block (in the world, of course) in a certain radius (yes, I tried the template, but for some reason it didn't work...maybe I was using it wrong).
3. If it finds it, move to it and mine it (by which I mean, basically, remove it with particles and add one of that same block in the storage slot in its inventory).