using a 6.0M stock solution and a 2.5M stock solution, create two 0.01M solutions of hydrochloric acid with a 250mL volume

Using the 6.0 M stock.

mL1 x M1 = mL2 x M2
mL1 x 6.0 = 250 mL x 0.01
Solve for mL 1, add that to a 250 mL volumetric flask and make to the mark with DI water.

2.5 M stock is done the same way.