How do I get access to the router to perform a soft reboot?

You have not mentioned which model but for most draytek routers
type 192.168.1.1
At log in page pass & user name is ... admin/admin (default) some routers the pass is blank (dont remember which ones sorry)
Go to System Maintenance >> Reboot System & Do you want to reboot your router ?
Choice "Using current configuration" usually is selected by default and click button "reboot now"

Via telnet for router is "sys reboot"