Trimless downlights and linear lights have been around for a few years. If you have access to good tradesmen i.e. a good general builder or plasterer and electrician they can work together to provide the most discrete lighting in your space.
Firstly and most importantly to use these lights in your space you must:
a, be prepared to put a skim coat of plaster on your existing ceiling
b, fix the lighting in place before a skim coat is applied to new plasterboard.
Assuming that this is the case the process is as follows:
1, Consider carefully where and joists or other obstructions are before marking the position of the light.
2, Cut the hole for the light fixture following the dimensions supplied with each light.
3, Fix the plaster-in housing in-situ with screws or clips as detailed in the instructions.
4, Adjust the position of the bead to suit a 3mm skim coat.
5, Plaster and paint.
6, Install the remainder of the light fixture and lamp.