New To Ren (sustaining notes to make instruments/patches)

Issue in question...
I have a bassline and want to take just one note of that bassline to make my own chromatic instrument. What is the best best way to make one note loop seamlessly? Is there a crossfade looping feature perhaps? What would be the best way to go about this on the Ren? Thank you in advance for any help/advice anybody can offer.

No crossfade looping, all you can do is pick a region of fairly constant amplitude and experiment with the start and end points until you hopefully get lucky. I cover this process in detail in my Ren book, but ultimately this is one of the areas where the Ren is lacking (well, all of Sample Edit is IMO very threadbare considering we are now in a computer environment - it really doesn't offer much more than the basic editing features found in the TRIM screen of a legacy MPC).

I suggest you head over to a proper audio editor to create your instrument sustains and then import them back into the Ren.

ty, I thought is seemed rather thin in this department. If you would be so kind, what audio editors might you recommend and would I be able to do this in Studio One?

Not familiar with Studio One, but I believe pretty much any well-spec'd audio editor should handle crossfade looping. Audacity is free and should accomplish this. Otherwise, usual suspects i.e. kontakt, soundforge, audition etc.