Ambient is about your approach, so how do you want to find or create the textures?
You’ll do well spend more time understanding sampling, how to start collecting textures, where to find them around you, what old sources on youtube or elsewhere can provide you with lo-fi, and then get better at degradation of the source material.
Burial’s process has little to nothing to do with synthesizers directly, and you can absolutely get closer than you think with only your Model:Samples!
Understand what sources to seek out, what thematic choices with vintage audio, understand how they were composed, look into trip hop and older hip hop sampling aesthetic (mid-heavy late 80s stuff that veers into slightly industrial processing like Public Enemy would also be fun.)
If you’re looking for textures to add, you can find some initial inspiration in goldbaby - dirt and layers
It’s fine to not start with that, but can give you an idea of what to isolate for.
To create your own sounds, you can edit ambient “silence” from movies and in something like audacity, to then upload to your sampler.
You can also do interesting things in Audacity with
Paul’s Extreme Sound Stretch
(an ambient godsend) and The AKAIZER Project can grunge up any source further.
This is of course creating starting material!
The trick for the tracks is to create a careful spacing between the noise and let the FX breathe and still be dynamic, not creating a solid cloud of smoke.
You want your percussive may-not-even-be-drum groove that the textures can slither in and out of, like a school of fish 
We are very happy to give tips as to how to do what you want with exactly what’s in hand, because what you are seeking is workflow and process!
And while perhaps difficult to get your head around, and we can’t promise we know burial’s secret sauce, the style and aesthetic are achievable and we all have our methods we can help you solidify your understanding of, or give you additional tools in your arsenal for emotional resonance and creating a similar aesthetic.
