How to control sample start time with the audio loop player?

[Quemis]

• So im making my second vst, and I have this audio file - its the only one I'll be using,
  to do a bunch of things with. I want the ability to only play a section of that and loop it. I got some ideas about how to do this via modulating a start time property of the audio loop player, only to find the only one that exists is "Random start time."

I don't think it makes sense to use a sampler when I only have the one short audio file.
Also, I tried using the sampler and couldn't really figure out a way to do what I wanted anywho.

I know there has got to be a way to do this.

Any ideas?