Hi @Harveen,
A warm welcome to the Bunnings Workshop community and thank you for your question.
I have a few questions for you that will help our members offer their best advice.
Where are you planning to have your planter boxes? Can you put a basic plan on paper with some dimensions and upload a photo?
How high do you want your planter boxes?
Which specific sleepers and posts did you buy?
You can use How To Build a Raised Garden Bed With Sleepers as a basic guide for building planter boxes.
For more specific advice, I'll need more details. Once you've answered the questions above, I'll be happy to assist further.
Jacob
