The factory cab headlining is folded over the windscreen aperture and glued on. F.ord, for example, used little u shaped barbed clips to help hold the headlining in place, along with glue to secure it. That said, modern adhesives would probably be enough to hold it in place without clips ( bearing in mind such headlining isnt used anymore anyway, they are all moulded)
When I've re-trimmed roof linings after them being taken out for accident repair work, like fitting a new roof skin or repairing a dent for example, it was the norm to first hang it on the first rail at the front and work back and then fix it to the windscreen and door openings with glue, stretching it and fixing it as it progressed along to the back of the vehicle. The adhesive used then was 3m Fast tac, which was the proverbial s**t off a shovel stuff though the modern solvent free stuff around today won't perhaps be as effective
On my old van, I replaced the Holdsworth (villa3 pop top) headling with megavan mat material. Using a denim grade sewing needle in a domestic sewing machine, I made new seams, put the metal rod though and secured it to the nylon clips in the cant rail and then trimmed the material, stretched and glued it to the window apertures (glass out) and once the glue had set, refitted the windows. Where the material met up to the uprights by the windows I folded the edge of the headlining about a quarter inch, trimmed the upright with more material and then glued the headling edge up to that, to give a nice looking joint. I did the same where it mm et up to the factory join and it looked pretty good to my eye.
It takes time, but not too difficult to do if you are patient.
