Expect the placement to be the part that matters. Barriers are heavy, they are craned or hiabbed into position rather than nudged afterwards, and a line set out badly either leaves gaps a vehicle can get through or blocks access you still need. We agree the line, the openings and the end treatments with you first, then set the units out level and true along the run.
On temporary work the barriers arrive and leave on your programme. On permanent installations they can be pinned into the surface beneath and finished with a true top line. In both cases the units themselves ask for essentially nothing once they are set.
Give us the length of the run, what the barrier is there to protect and how a truck reaches the line, and we can scope it accurately.