Replacing a SRAM Force hydraulic caliper with a new one

This SRAM video on replacingthe hydraulic hose involves removing all the fluid from the system - the situation you are in now. At the end it says to bleed the brake then links to the standard SRAM bleed process, so presumably that's what you need to do.

The standard bleed process is designed to displace all the old fluid with fresh, so the lower syringe must contain enough fluid to fill the system. I think I'd repeat the steps for removing air bubbles a few more times than SRAM suggests to make sure the system is filled properly and there is no air left in the system. If the lever feels spongy you can of course repeat the bleed process.