Now that you have your Ultimaker, you're going to want to start printing. If you've purchased a Ultimaker 2 series printer, sample files are already present on your SD card. Ultimaker 3 series printers should have files on the USB stick (however, some older units may not).
Printing Sample Files:
Once you've loaded your filament and have the SD card/USB stick in your printer, you're ready to go. Choose "Print" on the menu and select your very first print. The Ultimaker robot is always a favorite. The bed will heat first, and then the nozzle.
The printhead will move to the front left corner and purge a string of filament to make sure that you've got a good, strong material flow. You may want to catch this filament purge with a pair of tweezers so it doesn't get caught on the nozzle.
If no filament comes out in the front left corner at the start of your print, go ahead and abort the print using the menu options. If filament came out when you loaded the material, but isn't coming out during your first print, please see this article regarding the loading process.
Finding Files Online:
There are plenty of places online where you can download files that others in the 3D printing community have made available and get feedback on what sort of settings work best for different files. Here are some popular repositories for prints:
Members of the 3D printing community frequently post files at these places which they make available. Be sure to check the copyright information; some items are creative commons non-commercial use only, others are creative commons share and share-alike.
To print files from any of these sites, find something you like and download the .STL or .OBJ file, and open Cura on your computer. If you haven't downloaded Cura yet, you can find the latest version here.
Choose "File" from the menu and "Open File(s)":
You model should appear on the print bed on your screen. If it's within the print area, it will appear yellow. If it's too large, it will be grayed out--don't worry, you can resize it. If the model appears to be very small, it may be in inches, rather than millimeters. Cura handles all measurements in millimeters for size, and Celsius for temperature. You can control the scale of STL model by selecting it, and choosing the double beaker icon on the left side of the screen.
Check the name across the table cover on your screen and make sure you have the right model printer selected. If you don't, go up to the "Settings" menu, then "Printer" and select your correct model from the list. If you do not see your model listed, choose "Add Printer."
Save your file and get ready to print. We recommend starting out with the Recommended settings in Cura; these have been thoroughly tested with Ultimaker filament and should provide good results for most prints.
For Ultimaker 2 series printers, you can save your gcode to an SD card to print. For Ultimaker 3 series printers, you can save the gcode to a USB stick, or (if your printer is connected to the internet) print directly from Cura over the network.
If saving your gcode file to an SD card or USB stick, please make sure to use safe eject processes when removing the card or stick from your computer. Time to print!
What if I want to make my own things?
There are a lot of different CAD programs out there that will help you design your own things to print. The best CAD program for you is going to depend a lot on what sort of objects you want to make, and how much time you can put into learning the software.
TinkerCAD is an easy to use, free, web-based design program. It's a great first step for learning to make and use 3D shapes that you can print.
Blender is a great, free and open-source 3D modeling program that can do a lot.
Zbrush is really excellent for organic shapes. If you're planning to do a lot of 3D scans that will need cleaning up (for example, if you were scanning people), Zbrush is a great choice.
OpenSCAD lets you create math based 3D models by writing code to articulate what you want your model to look like.
Autodesk has both 3D design and animation tools and is widely used.
SolidWorks is another widely used CAD program.