Once you logged into your account, click on the tab Create and then choose New project. Among the options displayed, you might want to use Survey Link. This type of project will allow you to request a code for the task to be paid. Hence, participants in your study will complete their task, see a unique code at the end (as shown in earnings.php in the tutorial) and then enter it as a code in this type of survey.
Select Create Project and fill in the required details for the tab Properties as you like (title, description, reward per assignment, etc). Select Design Layout (shown below). In this page edit the content that you want your participants to see, usually the title and description you already used in the previous tab will be enough.
Once you are done with the edition, press Source and search for the two instances where “http://www.linktomysurvey.com” appears. Replace them with the link to your own survey, press Source again and click on Preview. If you are happy with the way your task looks, press Finish; otherwise, go back and edit as you please.