First gaming pc

A very reasonable build.
I have a few suggestions:

1. On the ram, if you will forever be satisfied with 8gb, buy a 2 x4gb kit so you can run in faster dual channel mode.
If you think one stick may allow you to upgrade to 8gb in the future, buy your 2 x 8gb kit now.
Adding ram later will not be guaranteed to work. Both sticks must be matched, Even the same part numbers may differ and be incompatible.

2. RX470 needs all of that 430w psu.
I3-6100 is a very good gamer, if you ever aspire to upgrade your graphics card, use a stronger 500-650w psu in the first place.

3.
I will never again build without a ssd for the "C" drive. It makes everything you do much quicker.
120gb is minimum, it will hold the os and a handful of games. If you can go 240gb, or 500gb you may never need a hard drive.

I would defer on the hard drive unless you need to store large files such as video's.
It is easy to add a hard drive later.
Samsung EVO is a good choice for performance and reliability.