Moulded concrete for garden patio and path

Moulded concrete what? Paving slabs? They can be got in builders' providers, garden centres, firms that make concrete products, Roadstone etc. It depends on where you are.

Start by googling to find the products you are looking for, then go onto Youtube and watch some videos on how to lay/use them. Check out several because there are a few options for doing it and some videos are specifying particular products (in order to sell them), others make the job look way more complicated/easy than it is.

You say you are going to attempt to do the garden yourselves, which is great. You need to make a plan of exactly what you are going to attempt and what the final result will be. Divide the job into manageable chunks, do so much this year then the next phase next year, for example. Make sure you have not organised it so you will have to take (say) a digger across finished paving. Do you have to do any earth moving, do you have to accommodate slopes, have you allowed for draining water away from the house (slope of finished paved area) or ensuring there will not be puddles.

Be checking up on what products are available, and which you prefer, but buying the slabs is quite a long way down the list of what you have to plan.