Under the "Project" tab, if the procurement request is related to a project or a project and its WBS, you can select the project from the "Projects" window and link it to the document by sending the save. If you also want to link the project WBS, you can do the same.
If you want to associate more projects, you can select the first one, type the percentage and save. The system will show two more lines to add WBS elements with more projects and show the remaining percentage to complete 100%.
To delete project records, you must check the "Delete" checkbox and click the "Delete" button.