Hi Leon
Welcome to the forum. The Stuart 10V is a good start to engine building.
TEE publishing do a little book called Building A steam Engine From Castings. It is in print and about £9 plus postage,
There is a very useful website called mainstream.co.uk about repairing badly built Stuart engines.
I am not saying your engine will be bad but if you see the problems other builders have had, you can avoid making the same mistakes.
There is also a you tube series about building the Stuart 10V by, I think, an American builder that is well worth watching although some of his machining methods were a but suspect.