You can play on this page by drawing 2D molecules or by searching molecules on the NCI, or PubChem servers

Draw a 2D compound and then click on the → arrow to convert from 2D to 3D
or
Search a molecule by its name on the servers and click on the ← arrow to convert it to a 2D sketch. The scheme can be modified accordingly

Click on the "Show SMILES" button to see the simplified molecular-input line-entry system that describes this compound