Depending on your requirements, the following mounting might be useful.
I have used Scotch 3M Photo Mount in spray cans for at least 30 years. You should experiment on prints of no significant value until you’re confident that you can do so correctly. I generally mount on Foam Core boards. I begin by laying out two adjacent edges with soft pencil and a combination square. Then I give a light coat to the board and the back of the print, wait about 5 minutes and align one edge of the print with its pencil reference line and the end of the print with the other line.
Then I lay the print onto the surface. I flip the print and board print-side-down and lay it on a clean, particle-free countertop or tabletop and press down in the center of the mounting board and wipe the palm of my hand outward at 12 o’clock, 10, 2, 9, 3, etc. until I’ve done this all around. When I then flip the board-and-print assembly face up, the print is permanently mounted and is perfectly flat. By applying pressure in this manner there are no “hills and valleys” in the surface of the print, such as might happen by pressing the print directly with your hand.
It's a bit tricky to do this because 3M Photo Mount is type of contact cement. If you make contact between the two surfaces in the wrong point, you won’t be able to lift up to print to reposition it without ruining the print and possibly spoiling that surface of the mount. I have successfully mounted prints up to 16” x 20” in this manner, both RC and FB. It’s also possible to make a less-than-permanent mount by only spraying a very light coat on the mount board only. Experimenting with prints of no great value will help you to figure out how to get the results you want. I buy 3M Photo Mount at the Michael’s arts & crafts store in my area.