How to count Physical inventory by MI34 ?

Hi,

I have created Physical inventory document by MI31. Now I want count it by MI34. In MI34 i got default logical file name 'MMIM_PHYSICAL_INVENTORY_DOCUMENTS', after executing with tick on Issue log and Test data i got warning 'Sequential file phyinv34_38 overwritten with test data'.

Can anybody tell me in details how to process for mass physical inventory counting by MI34? I have gone through all threads of SDN but there is no step by step and detailed info available .

Thanks,

Pradeep