We will start with the program you WILL be using to print with the Ender-3, you cannot use Print Studio, Blender, Or Autodesk, you must use Cura. Cura can be found and downloaded here: https://ultimaker.com/en/products/ultimaker-cura-software (Or borrow computer 4 or 6 from a friend if it isn't already available for use, if you do this skip to step 2)
On this site if you scroll down you will see this button (first image), click it.
It will then show this pop-up (second image)
Fill out the required fields and hit download, if downloading on Mac OS (A Macbook (An Apple PC)) you will open the file from chrome (if you aren't using chrome download it here: https://www.google.com/chrome/) from the bottom downloads bar (third image)
You will then find this window open (fourth image)
Drag the cura icon onto the applications folder and cura should appear on the toolbar.
If you tap Cura from the toolbar this should pop up (fifth image)
Click the other tab and search for Creality Ender-3 it should be all the way at the bottom of the current window view. (sixth image)
Hit add printer and find a file to print, I recommend using this test shrek: https://www.tinkercad.com/things/8wWAjHGDFnd-shre...
Download this file via tinkercad.com and place it into Cura, you can do this by opening the file you want to print via the open file button. (Seventh image)
Afterwards this (8th image) should look like the 9th image
Step 1: Ender-3 for Dummies: the Filament
If there is not already filament in the printer you need to place the spool of filament onto the roller.
To insert or remove filament you will need to push on the lever indicated (1st image) and squeeze while inserting the filament into the hole to the left of the y axis screw. (2nd image)
To prepare for printing on the printer you need to first turn on the Ender 3 press the knob once and select “prepare” (3rd image) by turning the knob and pushing it in, then you would need to select “Auto Home” (4th image) and wait for the nozzle to move to the bottom/left side of the platform.
After it is done then select “Disable Steppers” to be able to move both the base platform and the extruder.
Now you should be able to start leveling the platform so that your print turns out in one piece. Use a piece of A4 paper (or card stock) to assist with the adjustments and make sure that you can just barely squeeze the paper under the extruder.
Do this with all four corners and repeat this more than once (caution: this printer will need to be leveled each and every time you use the printer).
Step 2: Ender-3 for Dummies: the Build
Now select “Print from SD” (1st image)
select “CE3_shrek.gcode” (2nd image) and let the printer heat up and begin printing.
If you want to there is a thing you can do once it starts you can turn up the printers “FR” or feed rate by going to the info screen (the screen that appears when you turn on the printer) and turning the knob to the right. This setting lets the printer determine the speed of the printers movements you can set it up to 100% or more (you can also go below 100% if your print is coming out wrong) this is what i recommend, but if you want to turn it up more or slow it down as much as you want, but i will warn you that the speed will affect the quality of the print (sometimes).
Now have fun.