Signing up for Project Fi is simple, just like the service itself.

With Project Fi invites slowly trickling out to a select few, the sign-up process is still a relative unknown. We wanted to pull back the curtain and show you just how simple it is to sign up for the new service offering from Google, and give a few bits of information on the finer points of the process.

So, are you curious about what it's like to sign up for Project Fi? Read on.

First thing's first, you'll need an invite. You can sign up for one at the Google Fi website, and wait for it to arrive. Google's trying its best to at least give some folks timelines for when to expect an invite, but right now it's still relatively random. Once you get your invite, the process is extremely simple.

Project Fi setup step 1

Take the invite, and choose the Google Account you plan on using — you should use your primary account (the one you use for Google Play, etc.), and if you plan to bring your Google Voice number it should be that same Google Account.

Then you choose what phone number will be associated with your Fi service — a current Google Voice number, a carrier number that you port to Fi, or an entirely new number. This is the "scary" step with lots of words and explanations that are somewhat confusing, but don't worry — it's not as bad as it seems.

If you currently use a Google Voice number as your primary phone line, don't hesitate to port it to Project Fi. You'll still be able to forward phone calls onward to other phones (and Hangouts on the desktop), and make outgoing calls from other phones and computers via that phone number. You lose specialized voicemail greetings and spam filtering, but those aren't worth not going over to Fi for. Just go for it — if you ever cancel Fi, you'll be able to send your number back to Google Voice.

You'll really prefer moving from Google Voice to Fi when you realize that if you choose to get a new Project Fi number it'll release your current Google Voice number so you don't have it anymore. This stems from Google's requirement of only having one Google Voice number (aka Fi number) per Google Account. If you want to keep your current Voice number and get a new Fi number, you may consider paying to port that Voice number to a new Google Account instead.

If you don't have or care about Google Voice, you'll probably want to port your current carrier number into Project Fi. That'll work just like it does when you're switching carriers — enter your information, and wait for the port to go through. The porting process won't finalize until you have your Project Fi SIM or Nexus 6 in hand, so you'll still have your current carrier service until you can actually use Project Fi. Onward.

Choosing your plan couldn't be simpler — you'll always pay a base price of $20 per month for unlimited talk and texts, and a flat rate of $10 per gigabyte of data (which also works internationally, by the way). The interesting part about Project Fi is that this is just your best guess as to how much data you'll use — for example you could pay $50 up front ($20 base + $30 for 3GB of data), and you'll get refunded for the data you don't use. If you happen to go over your guess, that extra data will just be tacked onto the next bill at the normal $10 per gigabyte rate instead.

You can choose between one and 10GB of data per month, but you're never locked down — at any point during the month you can change your plan, and the new price will kick in at the next billing cycle. So don't stress over what you choose on this page — you'll never pay at a higher rate for overages, and you'll never pay for something you don't use.

That's it for the plan, just one page — now you'll need a phone (or more specifically, a Nexus 6). If you already have a Nexus 6, you'll have to verify that you have the device to receive your Project Fi SIM. If you don't have one yet, Google makes it easy to buy one — you can only choose a midnight blue model (for some reason), but you do get a choice of 32 or 64GB of storage. You'll pay for the phone at the final step of setup.

After confirming your billing and shipping addresses for the order, you'll simply confirm your plan and your phone purchase one last time. You'll notice that there isn't any activation fee for the service, but you will pay applicable sales tax and shipping if you bought a Nexus 6.

You can choose to buy the Nexus 6 outright (at its new lower price of $499) or finance it over a number of months, and you can also choose to use a different payment method than the one you eventually put in for monthly billing of Project Fi. The payment methods you use will be coming from Google Wallet, so you'll have to set that up if you haven't already. Double check, press the "continue" buttons and your Fi service will be on its way!

Project Fi number port confirmation

When your Project Fi "welcome box" and Nexus 6 (or SIM card) arrive, you'll simply have to power up your phone and confirm that you really want your number ported to the carrier. After a couple of hours or so, you'll receive a notification that your number is now on Fi and you're good to go!

We'll be covering a lot more details about Project Fi going forward, so if you have your invite keep it locked on Android Central for continued coverage!