Based on the two distinctions you've read about (experimental vs. observational, and exploratory vs. confirmatory), we could imagine a 2x2 table, with every study fitting into at least one cell:
Exploratory | Confirmatory | |
Observational | ... | ... |
Experimental | ... | ... |
In other words, there are exploratory observational studies, exploratory experimental studies, confirmatory observational studies, etc.
Try to fill in this table with examples. For each cell, describe a study (it could be a real study you've read, or a fake one you make up) that fits that category.