All these sites have guidelines and most have video tutorials to help you. Or why not teach yourself on - www.w3schools.com
However, if you are feeling a little daunted, it might be worth thinking about getting help. There is plenty of expertise out there and great local web designers to help you.
If you do want to appoint a web company, make sure you use your website brief to go out for quotes, ask to see examples of their work and get references from previous clients. Don’t be afraid to ask questions if you do not understand something – it is their role to explain. The more detailed and clear you make the brief, the easier and more understanding the designer will have. Look at the web designer’s own website; if it isn’t good, then that speaks volumes.
Also, don’t duplicate what is already out there. There are widgets and plug-ins such as Google Maps, YouTube or TripAdvisor, which bring their information into your website.
Ask your friends and family to critique your website. Make sure all your links work. Check the usability and function. Can people find the information you want them to easily? You will be surprised at how many people use websites in different ways, so getting as many different people to test the site before promoting it is very important. Don’t forget to check on different web browsers too; your site can look different on Internet Explorer and Firefox compared to Chrome, and also on different mobile phones, e.g. Apple iPhone and Android. Ensure you build in enough time to test your site before “going live”.