In order to create tasks that depend on one another, you must first create one of the tasks in the chain via braindump or via the task creation bar at the bottom of your "To Do" list. Once this task is created, click on its task summary to show the full task details of that task summary. At the bottom of the page are "But First..." and "And Then..." sections, which are just task creation bars that will set up a dependency. In other words, tasks created in those bars will need to be completed before or after the task that is currently open.
You can also create dependencies directly in braindump. If you've already created the tasks, then you can use any of the following:
check account balance [then: #CADR]
check account balance
then: #CADR
call mom
but first: #DALN
call mom [but first: #DALN]
You can also create dependent tasks directly in braindump. Just indent, add "first:" or "then:", then the new task. You can even chain many tasks together, any way you like:
make dinner
then: eat dinner
then: do dishes
clean room [work]
but first: write report [school work]
but first: walk Tyson [pet]
but first: feed Chairman Mao [pet]
buy groceries
but first: start car
then: get in car
then: make dinner
then: eat dinner
then: do dishes
then: go to bed
Once you have created dependencies, only the first task in the chain will show up in your "To Do" list by default. The dependent task summary will show up in your task as hyperlink to the right of that task summary. You can create as many dependecies as you like. To create dependencies between existing tasks, you can enter the Task ID (i.e. #L4Z) into the appropriate "But first..." or "And then..." field. You can do this either from the task screen or from the task's dropdown menu to the right of its summary in a list. To undo a "But first..." or "And then...", you can select "remove link to (Task ID)" from the task's dropdown menu. This will make the dependent task its own independent task.