How to creat pressure load in Feap 7.5

 Please guide me if you know how to create pressure (following load) in Feap 7.5. I use BLOCk command to creat a mesh for a 1/4tube (commands below). Now I would like to introduce internal pressure but it seem to be difficult because manual of Feap for this content is brief.

Thank you in advance.

NH Nguyen.