Q1. What is the max/min period of HSMP we can get it ?
With new rules, you will initially get HSMP visa for 2 years and then when you apply for FLR (Fixed leave to remain) after two years, you will get it for next 3 years and after completing 5 years of your stay in UK, you apply for ILR (Indefinate Leave to Remain). After 1 year of receiving your ILR, you can then file a PR which will leads to British Residancy.
Q2.Family is not here still i can get the hsmp visa stamping for them.
You can get your HSMP visa stamped for your family from the British Embassy in the country your family is presently who can then join you in UK.
Q3. After getting hsmp visa, what is the period i can stay outside country ? How often i can go & come to home country ?
During your stay for 5 years before getting ILR, you can be outside UK for a total period of 6 months not exceeding 3 months at one given point in time. But there are exceptions buring business travel and others which you will get the information from Home Office Website.
You can travel your homecountry as often as you wish but keeping in mind the 6 month rule.
Hope that helps!!