HowTo Setup The Backend Admin of WP in English & Frontend in Another Language!?

Hey Guys,

I'm an English speaking Aussie, & I have just taken on building a business WP website for my Vietnamese brother-in-law's new bathroom-supplies startup-website located in Vietnam.

I'm doing everything from A-Z...from domain rego, to hosting setup, to WP install, premium theme and plugin config, to adding all copy/images/pages/posts etc.

What I'm really lost, and confused about is.... I need the WP Admin/back-end to ALL be in English (for me) but all the front-end Page-Copy/ Navigation/ Links etc...what a person browsing the site sees, for it to be in #1 Vietnamese Language (for local Vietnamese people visiting the site) ...so I'll be pasting in Titles, page-copy in Vietname, int he backend then hitting publish.

Also, at some point I'll learn how to add a language switcher/button in the Top Navigation using WPML or something so that #2 an English translated version is view-able.

Can you please please please give me some advice, guidance or tips on how or what I need to do to make the above happen, to have the backend in English so I can use it, to copy and paste all the Viet language page copy, link and menu labels...so that it works and Vietnamese font types/characters display correctly?????

Thank you very very much