The pond that Bill Built..... continued.
The form is approx 18x18x 1 1/2.
The form is designed in such a way that even though the edges look irregular, they are all interlocking when placed side-by-side.
Basically, 2 bags of Qikrete, Home Depot brand of sand and cement mix, will fill the plastic form 3 times. They have cement dye to color the cement more naturally to get away from the gray color. I used Terra Cotta. Do not follow the instructions on mixing the dye. What I found best is 1/3 bottle for each batch (2 bags). This gives a light natural appearance. If you follow he directions on the bottle, you end up with a color like a clay flower pot. 1) Prepare the area for the path. I am in sandy soil so all I did was dig it out so the top of the form was level with the top of the soil, maybe a little higher. 2) I would mix 2 bags in a wheelbarrow then add the dye and mix well. Don't make it too soupy, make it kind of stiff. 3) fill the plastic form with cement, work it into all the edges and let stand for 5 to 10 minutes, firm enough so you can remove the form and the cement will not droop. 4) move the form to the next location adjacent to the just poured blocks and do it again.
About 2 days later I will fill in the spaces between blocks with light dirt and sand mix. Work into the groves and sweep it. Looks like it has been there for years!
Good luck!