in vor dme or other chart like rds landing based by my self choose how much v/s i will use. i am using airbus a320 and always use wrong v/s and i do not land. look the chart is vor dme of lgav. So how i will know the correct v/s to go down to runway.
Depend on your groundspeed. See the table in the row called Descent Angle. There you have the v/s for different groundspeeds: Groundspeed 140 kts gives a v/s of 924 feet/minute
Since you are using the Airbus, you may find it easier to use FPA instead of VS.
As Torben points out, Jeppesen is so nice to give you values for your VS based on various GS which allows you to quickly estimate a rough rate, otherwise - if the glide path is 3° or at least very close to it, which is not the case for this specific approach but for most others, you can also use the following rule of thumb: GS x 5 = VS.
At the end of the day, with non precision approaches like these, you would use the PAPIs and/or the runway picture for descent guidance as soon as you can see the runway, so unless you come across the occasional very bad weather, you usually don’t have to do too much maths 