Many thanks for your 5* review. I'm sorry to hear that you were struggling to use the Garden Planner at first, but I'm very glad to hear that we were able to help. I will forward on your comments about the video tutorial.
Many people create the Plan the size of their whole garden then add beds for their plants and add paths, etc. However, you can also create each bed separately as you can create up to 5 Plans per calendar year. As you say, the minimum size is 3'3"x3'3", but if your bed is smaller than this, you can either add a raised bed icon from the Garden Objects, or use the Shapes Tool to draw your bed. The minimum size of your Plan is 3'3"x3'3", but larger than this, you don't have to have the odd 3", your Plan can be any size you like.
As for the height and width of your Plan, this is the height and width as you are looking at your screen, rather than your actual garden.
It is possible to choose Jalapeños as a chilli variety and add Broccolini as a broccoli variety. You can also create custom plants by editing any existing plant icon.
Your Plan will autosave every 10 minutes, but you can also use the save button whenever you have made any changes. You can also save your Plan as a PDF if you are worried about losing it.
We'll contact you with details of how to do all of these things. Do also let us know if you have any more questions.