Sorry this is probably the most stupid question on this forum but I accidently clicked the x on the timeline and I have got no clue how to reopen it and I've got something due tonight :/.
Window > Timeline
Thank you so much I'm gonna speedrun this assignment now.
Good luck, mate!
Nick gave you an exact answer, but a related thing to know about is workspaces. Choose Window menu, Workspaces, and try out some of the presets. A few of them feature the timeline, but also arrange other panels in a way that makes the best use of your screen, for that kind of workflow.