Ok I have never grafted anything befor but I have an older shimpaku Juniper that I have shown befor and I would like to try and fill in some of the bald spots by grafting. I just got two smaller junipers of the same species and I think if I slip pot both into there own containers I should be able to do the graft easily, any ideas on how to keep the slip pots were I want them as not to damage or fail the graft, and any ideas on were I should graft onto the older juniper?

It's not my tree, but...
Why grafting? Just to get the hang of it?
I think your juniper is too tall and the trunk has no taper, and IF it were mine, I would cut it down to the second branch instead of grafting anything.
My two cents.

I understand that, the tree was designed like that from the owner befor me and is supposed to have dead wood down the side, I'm not sure of the end result but this is one of my teachers trees he gave me so I'm not sure what to do

Make a quick design or a virtual on Photoshop before cutting or grafting anything; start from your vision of this juniper's future.