pretax 401k conversion to personal roth account

Hi,

 

I plan to move my previous 401k account (let's say it is $5000) to IRA account ($5000). Then, move the money to my ROTH account. If I put zero as my withholding while doing this conversion on Fidelity website, how should I pay for the tax for this conversion (let's say the tax for this conversion is $1000)? Could I put $5000 from IRA to ROTH (since withholding is $0), and draw $1000 from my bank account to pay for the tax when I file the tax return for the year, or should I take $1000 out of my ROTH account (similar to a distribution) and pay for the tax at the time to file the tax return for the year?

 

Please advise.