HR infotypes report

hi All,

i am new to SDN and as a matter of fact this is my first post. I am given an assignment to produce a report that displays the career history of an employee depending on the pernr. wat they desire is to show how long the employee has been wid company and at wat position. they also need to exclude those months when employee was not with company. this is my first assingment with HR and only info i have got is infotype PA0001 wud be used and HRP1001. I want to knw where can i find information about the dates the employee was with the company and wat was his position then. Also its a requirement to find GMC, if someone cud focus on wat GMC means, its found in infotype HRP1001.

thanks in advance,

Reena Sharma...