Choose the right location. Measure for the first support post. Measure for the middle post. Mark the lines for the support posts. Mark the height of your garden bed. Measure and cut the support posts. Mark for the holes in the support posts. Drill the holes in the support posts.
For those less inclined to DIY, raised beds can be bought in kit form, with a. Disadvantages: Sleepers can be expensive to purchase and can potentially leak
Jarrah railway sleepers are fairly cheap for their size, and would make great raised beds. I'm thinking of using them to create a terraced vegetable plot, with the .
Put soil into the trench to ground level. Line the sides of the bed with a waterproof membrane. Break up the soil surface with a fork. A bed made from railway sleepers will be extremely strong and long lasting, with an attractive natural look.