The RAW says:

"When you first gain the ability to cast this spell, you learn the sigil sequences for two destinations on the Material Plane, determined by the GM"

Does the caster upon learning know where the 2 sigils go too. Or, do they just know the sigils but do not know where they go to until they actually go there?.

Quote from Terran_Gray >>

The RAW says:

"When you first gain the ability to cast this spell, you learn the sigil sequences for two destinations on the Material Plane, determined by the GM"

Does the caster upon learning know where the 2 sigils go too. Or, do they just know the sigils but do not know where they go to until they actually go there?.

 Raw: you learn the sigila for the destinations. Up to the DM to tel you the destinations or not before you go there. Otherwise you have to travel there to find out.

rai: you’re probably supposed to know.

I would think you should know what the destinations are.

I would never cast the spell if I didn't at least think I knew where I was going.

I was thinking the sigils are like a phone number.

You could find the number written down somewhere, but do not know where it connects until u go there

Up to the DM. The intent is that you know (a wizard taking this knows it as part of their research into developing the spell, a sorcerer might "feel" the nearest two circles and learnt them that way when the power unlocked within them, etc). 

It's left open for you to determine how your character knows the way you and DM want them to. Perhaps it means they know where it is, perhaps not - up to you.

I go on the side of "you know" - because it saves time and its hard to justify taking the massive risk of going to circles without knowing where they are or what might be waiting on the other side.