Step by Step:

Step 1: Go to Administration > Mobile > Mobile Dashboard
Step 2: Once in the Dashboard Click the Quick Items Button
Step 3: Click Add, then use your Inventory Tree to find the Items 

Step 1: If you know the Code, type it in on top and then click Add.
Step 2: For the Quick Items, click the Quick Items Button on the bottom of the app
Step 3: On the Next Screen the Quick Items will pop up, you can click the Add button to add the quick Items or Click the 'search inventory' button to search your live enterprise Database

Step 4: On the 'Search Inventory' screen you can type in part of your description, it should find the item in your database. 
Step 5: Click the button that looks like an eye to see it's availability.

Step 6: If the Item is available it should allow you to select the item.

Step 7: Once everything is selected, these items will be placed on the service order after you sync your Mobile.