Creation of overall enterprise resource pool to print resources current availability status to assign between projects

Hi Expats, Currently we are migrating projects from MSP to primavera, we are having around 20 projects and having more than 300 resources( labor non-labor and materials) in the enterprise, we are assigning the resources between all the projects, now the problem is how to check the resource availability without on the certain period of time without opening all the projects together? How to print the available units of each resources, current assigned projects? Kindly advise