IBM may have this procedure documented if you start an issue with them.
I doubt you will get much support for IMS V7. I have not kept track of IMS, but V7 might have gone out of support as much as 15 years ago.
Assuming you have all of the REL files, you need to examine each... the actual IMS deliverables are encapsulated with SMP/E statements. I think they specify the member name and what distribution file the member goes to. You need to remove the SMP/E stuff and put IMS member into the correct library. There are probably so many members that you would want to do so with a rexx program. There is probably a file type that has linkedit statements. You need to run the linkedit job to create load modules (SMP/E normally does that for you).
Get a document called 'program directory' and follow the post SMP/E instructions for installing and customizing. There should also be a manual for the Installation Verification Program. Read and follow the directions. Getting those documents for IMS V7 might be problematic.