When an activity depends on another activity, it means that one con not start until the other one finishes. We also call this linked activities. This normally happens in complex projects where many activities depend on many others. This can be confusing if not dealt with properly however, it can also help a lot in order to estimate critical paths and being able to prioritise your work.
Sinnaps will automatically estimate your critical path taking into account activities duration, time constrains and dependencies.
If you want to link an activity to another, select the activity that you want to link. Then you can click on the "link" icon of other activities in order to link the selected activity to them (As shown in the image below).
Why sometimes can't I move my activity to a previos date?
In the example above, you can see how Desing Context dependes on Design Objetives. This menas that Design Context can not start before Design Context ends. For this reason, it will be date constrains or dependencies on Design Objetives that will prevent us from moving Desing Context to a previous date.
In order to move Desing Context to a previous date, you would need to remove the dependency, change your project start date or reduce the duration of Design Objetives. However, many times this options are not realistic and make you foresee that you have a project issue that needs to be solved.
What happens when combining fix dates and dependencies?
In Sinnaps you can plan with both date constrains and dependencies. Both limitations will be taken into account when planning, however, when a dependency is not compatible with a date constrain, the dependency will ruleover the date constrain. If this happens, Sinnaps will let you know that an activity has "gone to automatic mode". Meaning that it now only depends on dependencies.