From anywhere in the application you can press Ctrl-F to search for a particular medicine. For instance, if you wish to order metoprolol but don't wish to click on "HTN" in the left hand side of the screen, simply press Ctrl-F, type in "metop" (without the quotes), and press enter.
To enter a PRN condition, generate the order sheet and then type directly on that sheet before printing. For instance, let's say you want to order Haldol for agitation, but only to be given overnight, not during daylight hours. Click the Haldol dose that you want, and click "Generate Orders". On the resulting order sheet, click on the end of the Haldol line and at the end add the text, for example, "q4-6h prn agitation only from 10pm-6am, all other times call MD".
If you forgot to select your name or you forgot to type in the patient's name, the first two entries of the list of categories on the left are "Provider Name" and "Patient Name". Click on either to go the corresponding section so you can enter the requisite information.
Also be sure to check out the FAQ and general Help pages.