How do I do this? What intervals are the strings tuned in? I tried it last night, but I thought I might break the strings.

Drop the E to C, A to G, D to C, G stays the same), B UP to C, and keep the E the same

So, CGCGCE overall

E: -
B: half step up to C
G: -
D: 1 step down to C
A: 1 step down to G
E: 2 steps down to C

Even though you're tuning your B up a little, I wouldn't worry about it breaking.

Which of those 2 is the one Devin uses?

They're both the same. I just said it in a different way.

But in one it is said to keep E as E, and in another it says to drop E to C?

You keep the high E the same, and drop the low one to C.

Oh, so the second one was from high to low. Got it.

concerning Open C.... I got a 4 string bass i want to tune to Open C. any string suggestions?

Nm.

concerning Open C.... I got a 4 string bass i want to tune to Open C. any string suggestions?

Just tune drop C. I.e. E down two steps, everything else down one.