When you mount the new seat, it is important to take care of three factors: height, inclination and setback. Please note to take all these measures on your old saddle, before mounting the new one.
The first measure is the height: the distance between the bottom bracket and the saddle ergonomic center (where the saddle has a 7cm width). This influences the knee ROM (range of movement). A non-ideal ROM can determine joint problems and other issues.
The inclination impacts the posture, on the pressure on the perineal area and on the low back tension.
Last but not least the saddle set back is very important in determining the most efficient position and to avoid knee problems.
Let’s start with the height: when you change your saddle, you must conserve the same setting as your hold one. To do so you need to measure before mounting the new one the height between the bottom bracket and the anatomical center. In this way, you can have a clear reference. Is it possible to do so with a simple meter.
When talking about the setback it is important to be aware of the fact that this value is different between a standard and a short saddle. If it is your first time with a short saddle, to maintain the same position on the bike, you need to consider the anatomical center, not the tip when taking the measures. In particular:
-Create a projection of the vertical axis of the bottom bracket. You can use a stick to create this distance.
-From this projection calculate the distance from the anatomical center. This is the measure to maintain, no matter the saddle’s length. If you consider the distance from the tip and then mount a shorter saddle, your position will be more backward, determining possible issues.
In the end, let’s set the inclination. To measure it on your old saddle it’s possible to use a level tool. If you have a round or semi-round saddle put the tool in the wider part, to be sure that the anatomical center is considered. 
There isn’t a specific rule regarding inclination. Every rider needs to find his ideal setting considering his disciplines, body features and bike geometry; to find it for the first time it is better to be supported by a specialist.
Once you have all these references to follow, just mount your brand-new saddle and fully enjoy it.
