Im new to blender, I accidentally dragged what i think is the animation timeline at the bottom of the screen upwards, and now It covers the entire screen. I dont know how to put it back, I tried dragging down from the top but it doesnt work. Please help.
You can put your mouse over the area border and press right mouse button, then select Split Area, and just move the split line to the proper place, and click. This should split the area to two identical areas. Next step is to change the upper area to 3d View (for example). Move your mouse there, and press Shift+F5.
To clarify, look at those pictures I prepared for you.
First, target your area border. This is easily found on horizonal or vertical area borders, where there are no other elements.
Next, press right mouse button. It should open the menu like this pictured below.
If you manage to open the menu, you are good to go. Just select appropriate option, which should split the area for you. Note, that you can change your mind and split the other way - either horizontal or vertical, just by pressing middle mouse button, when in "splitting mode". You will get the splitting line which looks like this:
If you want to split the area, press the left mouse button. The split will be done and you will get the same areas on both sides. This is the end of part 1.
Now, in order to enable any other area type in the upper part of the screen, move your mouse to it's center. It's important to not point anything substantial, no buttons, no panels, just the plain central area. Then you can press Shift+F6 to switch to 3D View. Or you can press any other combination: Shift+F1 (file browser), Shift+F3 (node editor), Shift+F9 (outliner), etc. Just name a few.
Note that in every area on the screen, you can find an "ICON" to change the view type. It is usually located in the left upper or bottom corner. Look carefully. I enclose few screenshorts of such icons for you to give some hints.