Rollover Roth and Traditional 401k Taxes?

I had both pre-tax and post-tax paycheck withholding from my previous employer for our retirement plan. On the previous plan administrator website, these two designations were shown as two different groupings with set dollar amount in each.

I have rolled all funds over to a Schwab IRA since changing my work situation and the new IRA account balance just shows a single lump sum. I specifically requested to leave each account as is with regards to tax-status (401k stays pre-tax and my ROTH contributions obviously would not change). I have not touched the balance yet to make any purchases/investments. How am I to make the distinction between the two groups or is this something I don't need to worry about until later? I don't want to come up on an unanticipated tax expense if the 401k portion was treated differently.

I don't know if I need to ask an accountant because Schwab doesn't have any distinction among the funds. I appreciate any insight!