What are the right steps to file taxes with no income?

I'm somewhat confused as to what exactly you're looking for. If you had no income, then you didn't pay any taxes. If you didn't pay taxes, then there's nothing to file.

They file in order to qualify for the Economic Stimulus Rebate, even though they have no taxable income.

Just file Form 1040A or 1040. There are special instructions on how to file to claim the rebate.

For stimulus rebate you must have minimum of $3,000 of qualifying income.

The qualifying income can be non-taxable, such as Social Security recipients or those on disability.