Survey the intended flowerbed area to determine the overall dimensions and the placements of the fencing and the paving stones. Designate multiple sections of sloping bed, separated by paving stone paths for easier walking between the flowers. Use a three or four foot distance as the ideal width of a sloped section from top to bottom.
Surround the flowerbed with low fencing or the treated lumber by planting the fencing deep into the dirt using a hammer or stepping on it heavily if necessary. Secure the treated lumber using tent stakes, rebar, or by simply embedding it deeply in the ground with the force of standing on top of it. You can also remove the dirt the lumber will occupy using a shovel and save the dirt for embedding the paving stones.
Arrange a path of paving stones horizontally, perpendicular to the direction of the bed's slope, so that the flower bed is separated into easily reachable sections. Build up the amount of dirt under the paving stone paths if necessary using extra soil to ensure absolute stability.
Spread a layer of fertilizer throughout the soil, and work it into the beds with the shovel. Plant your flowers in the desired manner, and lightly water with a spray to complete the flower bed environment.