The specs say you can install one 2.5" HDD plus one M.2 2230 NVME SSD. Doesn't look like there's enough space to install an M.2280 SSD. Instructions to install the SSD are here. Before you do the SSD installation, be sure to check the SATA Operation setting in BIOS setup. If it's set to RAID, you should reconfigure Windows to use AHCI before you install the SSD. There's a specific procedure to reconfigure Windows to use AHCI, so just don't change the BIOS setting without following the procedure. Otherwise you'll have booting issues. You can then use cloning software like Macrium Reflect (free) to clone the HDD onto the SSD. If the new SSD is larger capacity than your HDD, you'll need to know how to expand the size of the C: partition on the SSD to use the extra space, which varies with the cloning software used.
I recently replaced my hard drive due to failure but realize now I should have used a SSD instead.  Can you add a second drive to an AIO?  When I replaced the original, which was less than 1 year old, I don't recall seeing a second slot. Thanks Bob
AIO 5400 second hard drive