What multi port adaptor do I use to all me tp plug in my display, mouse and remote keyboard?

Your wired mouse and keyboards can be directly plugged into an available USB port on the computer, If none are available you would get a USB hub, connect it to your computer and then plug the keyboard and mouse into it. These hubs come in various sizes so you may want to get one which has enough ports to connect other peripheral devices as well. I strongly recommend that you only use a USB hub which has its own external power supply as many devices will not work when connected to a non-powered hub. As to the display, it may need it own adapter if it cannot be plugged directly into the computer. Check the display's specifications for specifics.