Add questions

Questions can be dragged from the left column into the middle one. A preview overlay will show you where the question will be placed.
Questions in the middle column can be re-ordered dragging them above or below other questions.
Notice some indicator icon on the right of each question:
A green check: the question is valid
A yellow warning sign: the question is invalid
A down arrow: the question has some jumps set
Once a question gets selected (clicking on it, it also gets a purple colour), its settings panel appear on the right, divided in:
Properties
Advanced
Jumps
Properties
Here is where the basic properties for a question get set. 
Question Text
The question text is always set here. 
Just type your question and you are good to go. You MUST have some text set for each question, or the question will be invalid.
A project can be saved only when ALL its questions are valid.
On this panel you also have the option to set a question as:
Required
The answer is required by the user to proceed with the form.  
Title
the answer will be used to identify a single entry when viewing the entries on a device or on the server (Read title section for more info)
If the question is of type README, you can only specify some text to be shown, and basic formatting is available
If the question is of type RADIO, DROPDOWN, or CHECKBOX, you can list all the possible answers here as well. Just click on "Add Answer" and modify the placeholder text with anything you want. You MUST have at least one possible answer set.
For LOCATION, PHOTO, AUDIO, VIDEO, BRANCH, and GROUP you can only specify the question text.
Advanced
Advanced settings depend on the question types. If the question does not have any advanced setting the tab will be disabled.
Initial Answer (default answer)
The input field on the device will be pre-filled with the value set here, think of it as a default answer.
Regex
The answer MUST match a regular expression. A regular expression (regex) is a special text string for describing a search pattern. You can think of regular expressions as wildcards.
You are probably familiar with wildcard notations such as *.txt to find all text files in a file manager. The regex equivalent is .*\.txt (What is a regex?)
Double Entry
Require double entry verification: two identical answers must be provided to proceed. It is useful for confirmation, like a code or an email.
Uniqueness
Make answer unique (form OR hierarchy): the answer must be unique. You can select if you like to have it unique for any entries belonging to a form or just for the children of a particular entry (hierarchy). More on uniqueness.​
Date & Time
For DATE and TIME questions, a selection of date or time format is available. You also have the option to set the current date or time when the question is shown on the screen ("Set initial answer to current date" checkbox).
Numeric (Integer or Decimal)
NUMERIC questions: a min and max value can be set. Also, there is the option for the question to be decimal (float) or integer.

Jumps
Jumps are a way to set up conditional logic on your questionnaire.
Jumps allow you to define that, based on the choice made by a user, they will 'jump' forward in a form to a question further along in the questionnaire or carry on to the next question. For example, if for question one in a form, the user selects choice one in the dropdown, jump them forward to question five, else continue on to question two.
Single or multiple jumps can be defined for a particular form input and can jump forward to any kind of form field (text or media) or to the end of a form. More on jumps.