To create a new project make sure that you are logged in the Joomla backend and then go to -> components -> CTransifex -> projects. Click on the "new" button. On the new screen you will see a form. When you hover with the mouse over a field label you should get a tool tip explaining what this field is for. The fields that are maybe new to you are:
Transifex project slug - this is the project name as defined in transifex. Make sure to enter the correct name here - otherwise we won't be able to get the details for the project from transifex.com
Extension name - this is the name that we will write in the install.xml for each language package. This would generally be the name of your extension. For example com_hotspots, com_ctransifex etc
Transifex config - just copy paste your .config file for that project in this field
The transifex config is very important. We use it to match the resource names to actual file names and to determine if the resource is a backend language file or a frontend language file. Whenever you add a new resource to your project in transifex you should update this field with resource definition as well. Otherwise we won't be able to fetch the file and add it to the language pack.
We determine if a file is a backend or frontend language by searching for the words "admin", "administrator" or "backend" in the file_filter for each resource. If we find that word we will place this file in the admin folder. If the file_filter doesn't contain any of those words then it will be treated as a frontend file.