Can -- Sampling time point of -- 87.5%

Hi,

I am going through this good application note from philips AN1798.pdf.
>> 4.1 Step-by-Step Calculation of Bit Timing Parameters

Here no where it is mentioned about achieving correct sampling time point.
Canopen suggest to use 87.5% sampling point

1> How shall we start the calculation of time quanta for segments to
achieve  -- 87.5% sampling time point?
2> What is the formula to calculate sample rate of bit ?

Please suggest.

//John