I remember it as consisting of three things: Open the PCRA, fund the PCRA, and finally allocate (any) future contributions to the PCRA.

You'll allocate funds to the PCRA just like any other fund in your 401k by designating a percentage on the 401k site. PCRA is an option in the list of funds. You can allocate 100% into the PCRA.

The thing I can't remember, nor can I find, is the initial investment amount to "get things going." I want to say it's $1,500 but that could be wrong. I went back and looked and $1,500 was around my first transfer amount to the PCRA when I opened it. PCRA was "grayed out" in the list of investment options on the 401k site where you designate the percents until there is enough funds to meet the beginning threshold.

I was new at F9 so I used another fund in our 401k to collect enough to get started in the PCRA. If you have that amount already then you can probably open the PCRA and then on the 401k site go Manage Account -> Investments -> Transfer and choose what you want to use to fund your PCRA with that minimum (or greater) amount. Once you do that you can then designate the future contribution % from your various sources (non-elective/elective, traditional/Roth).

Just a note that once you're rolling in the PCRA you'll log into a different Schwab site with different credentials to manage the PCRA. All contributions "hit" the 401k plan first, then transfer at the designated % to the PCRA where they settle in the "cash" account. From there I manually login and buy the funds I want.

Hope this helps.