The manual shows space for a 2.5" drive, but before buying one, check to make sure the mounting bracket, cable and screws are present in the system.  If they are not, you will need to order them from Dell Spare Parts. Subject to using a boot manager from the M.2 drive, you should be able to install one OS to it, and one to the  SATA drive.  
Hi all, I have a question regarding the use of multiple SSD in this system.  I have bought a Dell Vostro 3405, with an AMD Ryzen 5 3450U,  AMD Radeon Vega 8, 8GB of RAM, and a 256GB SSD M.2 storage unit. I understand that it also has a SATA slot. ¿Can i use a SSD SATA along with the M.2?. And another question, I have a SSD SATA from my old laptop, with Ubuntu as the operating system. If i can use the SATA along with the M.2, ¿can i have one with Windows, and the other with Linux?  Thanks in advance
Storage and OS (Dell Vostro 3405)