I need help

Hey guys i bought a dell pc that has a vostro 3888 boot manager and it had a hdd drive i bought a ssd and tried wiring it with the sata and power conector i started it it wouldn't boot to anything but the hdd i tried unplugging the hdd and trying to start it and it says there is no bootable device i tried using a usb windows installer and it doesnt even recognize it i reblugged the hdd and saw that the flash drive is there and the ssd is there too I shut it off and pressed f12 and there is no flash drive stick to boot from help anyone who ca help