The Institute Organizing Committee reserves the right to assign hotels based on a first-come-first-served basis.

研习会筹备委员会保有权利，对先到先服务之原则。

youdao

All bookings will be processed on a first-come-first-served basis. The Organizer will not guarantee the availability of tickets.

所有订票申请均以先到先得方法处理。主办单位不能保证所有订票者均能订得门票。

youdao

Tickets are available on a first come, first served basis.

票先来先买，售完为止。

《牛津词典》

Note that supplies are limited, and systems will be sold on a first-come, first-served basis.

ENGADGET: Wii U gets midnight launch at Nintendo World Store on November 18th

Tickets will be distributed -- one ticket per person -- on a first-come, first-served basis.

WHITEHOUSE: You're Invited: Join the White House Fall Garden Tour

However, the White House will distribute tickets for fall garden tours to the public on a first-come, first-served basis.

WHITEHOUSE: You're Invited: Join the White House Fall Garden Tour