I need help with chemistry. My teacher asked me to prepare a serial dilution from 1g Lithium Carbonate powder. I dont understand how?

The first step is to prepare stock solution of lithium carbonate:
In a 50-mL beaker, stirring with a glass rod, dissolve the 1-g lithium carbonate powder in a small amount of distilled water. Transfer the solution to a volumetric flask (say, 250 mL). Wash the beaker and the glass rod three times with a small amount of distilled water and transfer all washings to the volumetric flask. Add distilled water to the volumetric flask until the meniscus reaches the mark. Mixed well the stock solution.

The second step is to prepare a series of diluted solutions:
Label six test tubes as A, B, C, D, E and F. Using a burette, add 1 mL, 2 mL, 3 mL, 4 mL, 5 mL and 6 mL of the above stock solution to each of the six tubes A, B, C, D, E and F respectively. Using anther burette, add 9 mL, 8 mL, 7 mL, 6 mL, 5 mL and 4 mL of the distilled water to each of the six test tube A, B, C, D, E and F respectively. Now, each of the six tubes has 10 mL of solution and the ratio of concentration of carbonate from test tube A to F is 1 : 2 : 3 : 4 : 5 : 6.