Hiring a main contractor
The simplest option may be to ask a single building company to do all the building work for you. This makes them the 'main contractor'.
You should try to ensure that the builder you choose is suitable to do your work. Look for appropriate certification by trade bodies, seek local recommendations or ask your architect. Some trade organisations, like the Federation of Master Builders, can help you find a local contractor.
When you arrange a contract with the company, you should ask them to agree to a fixed price for the workwork – including any extra tradesmen they may have to bring in. This makes sure there's no risk of any hidden costs later on.
Hiring a main contractor is a common way of having a house built and your architect will be comfortable supervising a project like this.
If you choose to go down this route, seek legal advice and enter into a contract with the building company so you're protected in case something goes wrong.
An alternative to legal advice is the Scottish Building Contracts Committee website, which gives you a selection of pre-made contracts to choose from. There's a charge for this and it's more complicated than getting a professional to do it for you, but it saves time and legal fees.
When you hire a main contractor you should make sure your house plans are final. Although the company's price is fixed, if you decide to make any changes to your plans later you'll have changed the terms of your contract and the company can charge you more to carry out the changes.