Raised patio
I really can't tell you exactly how to build your own patio. I can give you the basics, and I can explain why things are done in a particular way with particular materials, but I can't tell you what type of retainer to use or how deep to dig the footings as I have never seen your plot and am not familiar with the exact layout.
The retainer can be brick, or an edging kerb, a flag-on-edge, a timber edging or old setts or anything you want - you only have 300mm of lift so you're spoiled for choice. If you want to use bricks, I would use 225mm engineering brickwork on a 450x100 concrete foundation at a depth of not less than 150mm, but, fo only 300mm of lift, that seems like a lot of work to me.
For the fill, you should only use inert material, so no soil. DTp1 is the best material, but you could use gravel, all-in ballast, crusher run or lean mix concrete if you preferred.
You need to come up with a plan for this patio before you start work. All the questions you might have are answered on the main site, but it involves you making decisions on what you want it all to look like once it's finished, how confident you are with your own skills, and how much you're prepared to spend. I can't take these decisions on your behalf.
The retainer can be brick, or an edging kerb, a flag-on-edge, a timber edging or old setts or anything you want - you only have 300mm of lift so you're spoiled for choice. If you want to use bricks, I would use 225mm engineering brickwork on a 450x100 concrete foundation at a depth of not less than 150mm, but, fo only 300mm of lift, that seems like a lot of work to me.
For the fill, you should only use inert material, so no soil. DTp1 is the best material, but you could use gravel, all-in ballast, crusher run or lean mix concrete if you preferred.
You need to come up with a plan for this patio before you start work. All the questions you might have are answered on the main site, but it involves you making decisions on what you want it all to look like once it's finished, how confident you are with your own skills, and how much you're prepared to spend. I can't take these decisions on your behalf.