You can run tasks in parallel within a job. Each task you select to run in parallel will run at the same time. For example, if a job has 3 tasks, you may want to execute steps 1 and 2 in parallel. You can enable these two tasks to run in parallel and when this job is run, these tasks will run at the same time while any remaining tasks will run sequentially.
Please note that a task that has a dependency on the previous task cannot run in parallel with that task. Tasks that have been selected to run in parallel also cannot have a dependency on each other. If a task is dependent on a parallel task, the dependent task will run after all parallel tasks have completed.
In the following image, I have chosen two tasks to run in parallel. During the next execution of this job, these tasks will run in parallel and not sequentially.