I just got a flp level 4 tranny 4l60e with a transgo vac mod port on it. my question is where does this tie in and what type of hose do i use?

 

If the port is there, then they should have given you the neccesary hardware to complete the install, and if they did in fact install the modulator. There should have been a clear hose with a spring like hose inside the clear one and a 'T' connector to hook up to the brake booster line.