How to hook up Pro-ject Headphone Amp

I have a Pro-ject Head Box MkII just bought on Audiogon..It is my 1st headphone amp.Will use w/ AKG 701 phones.CDP is Azur 840C. Pre is BAT 31i.Amp is Cary 88R. What is best way to connect the Pro-ject to this system? I can use RCA terminations on I/Cs.
Thanks for any advice.
insert into tape loop is preferred; if the headbox has a loop out, it can between the CDP and the pre, also.