It is very easy to model utilizing your HSA account to fund your healthcare expenses in the Planner.

STEP 1: Head over to My Plan > Money Flows

STEP 2: Scroll down to Transfers

STEP 3: Press "Add a Transfer"

STEP 4: Enter a transfer from the HSA account to the after-tax account with the lowest growth rate. This account has priority for funding expenses in the Planner.