Hi everyone, I have created a suitelet to submit a time-entry for a selected project and now need to make a workflow that sets the status of the project to "In Progress" when a time-entry is submitted for that project. How would I go about starting this, I'm lost after looking around for quite some time

Perhaps a scheduled workflow on projects that looked for time records connected to each project, if there are any, set it to "in progress". This would have a delay from when the time-entry is created. If you want it instantly, I believe you would need some sort of script. Either in the suitelet itself, a custom workflow action or a user event on the time-entry.

The best option I see is to add on your suitelet a record.load on the project and change the status if the project is not yet "In Progress"