Hello Anju,
Are you using a .csv format file? Did you make sure your mapping fields are correct in terms of order. use comma as a separator as appropriate. For File format, based on your need you need to have your own format (in excel and then convert in .csv) as you are creating a mapping format in the order fields are present in that file. First try with only a few key fields I would say.
Try to run the ELM using the option "Immediately" before you start and then press refresh. You should see the outcome under "Process Steps" with hopefully all green lights. If there is any red mark you can click on the link next to it and read the error. I am assuming you are trying to create Business Partners in CRM so if your ELM ran successfully you should be able to see the numbers under "Show List Records".
Aparna