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.
Printing Sample Files:
Once you've loaded your filament and have the SD card 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 great 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 "Load Model File."
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. Scaling it up by 2.54 using the scaling tool on the bottom left corner 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 Machine menu and select your printer from the list.
Save your file and get ready to print. You can use the Quickprint options, which are built in to Cura. However, for the best print results, we recommend learning to use the advanced settings for choosing things like your layer height, speed, an infill percentage.
If your SD card is inserted directly into your computer, you should see an image of an SD card between the Load folder and the YM icon. This will save your gcode (the file format the printer reads) directly onto the SD card. You can then eject the SD card and it put it in your printer and begin to print.
If your SD card is not inserted, or you are using a USB to connect an external SD card reader, you will see a save disc image instead. The .gcode file will save to your computer. You will then need to find where you've saved it and move it onto your SD card.
Eject your SD card with your new file on it, and insert it in your printer. 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.