Some of the older 15-series laptops have “non-user accessible” memory slots, meaning you have to disassemble the whole machine to get to the RAM. In my opinion, that’s more trouble than it’s worth unless you’re confident about what you’re doing and are willing to accept the risk that the computer might never run again.
Fortunately, newer models in this series, like my 15-f272wm have a user accessible “service door” on the bottom, which is held in place with two screws. Upgrading the RAM is at most a five-minute job and easily accomplished by anyone with reasonable screwdriver skills and a little patience. Just power down the computer, unplug the power cable and remove the battery before loosening the screws and removing the service door. The one and only memory slot is just inside the door. To install the maximum 8GB of RAM, you will first need to remove the original 4GB memory stick. Just spread the retaining clips on either side apart and the memory will tilt up and lift out. Set the 8GB memory stick into the slot, contacts first, and then gently press the top edge until it clicks into place. Then replace the service door, reinstall the battery, reconnect the power cord and restart the computer.