I encourage you to keep going with the journal entry report!
1) You will find it easier if you test your report in the preview sandbox as nothing much should be happening there. Your initial filter is as simple as "entry date is today" (or if you've been in the sandbox for a few minutes, maybe look at your watch and have it be "entry date is greater than Aug 4 at XX PM") and you will then begin to pull up every change you make, that your system tracks (see below handy hint).
2) I would start by including the Old Text Value and New Text Value columns in your view. These are the most likely places that would store that type of a change.
3) After you've created your report (hint: your report should start with no rows), you can change a project's program, and see if it shows up in your report (hint: after you make this change, your report should have at least one new line)
Handy hint: If you make a change to a program, and it doesn't show up on your report, it means you need to go to the setup area and add the program ID to your tracked fields area. This is under Interface / Update Feeds. The reason certain changes don't show up is because Workfront doesn't track everything, in particular the thing that isn't showing up. You have a limited ability to track things (for instance, I don't think you can track calculated fields), but the program ID should not be an issue.