You can select individual pages from the site map below, or work through the series in sequence by using the 'next' link at the foot of each page. Some pages have links at the bottom to interactive activities designed to help you check your knowledge. These activities open in new windows. When you have completed the activity click on the 'submit' button to check your results. If you need another try use the 'reset' button. Click the 'close this window' link at the bottom of the page when you have finished the activity. You will find the answers or methods for the activities in the tutorial. Two activities include a help link should you get really stuck.

You can select individual pages from the site map below, or work through the series in sequence by using the 'next' link at the foot of each page. Some pages have links at the bottom to interactive activities designed to help you check your knowledge. These activities open in new windows. When you have completed the activity click on the 'submit' button to check your results. If you need another try use the 'reset' button. Click the 'close this window' link at the bottom of the page when you have finished the activity. You will find the answers or methods for the activities in the tutorial. Two activities include a help link should you get really stuck.