New Collector Needs Help?

The bottom one looks like Constantine. That's the only ancient I really know about. I don't collect em. I'll let the experts on ancients take over.

I've found the Wildwinds database, particularly their partial inscription search engine, to be most useful as a "first stop" in identifying ancient coins. You simply type in all the letters you think you can read, and it finds all the coins that contain those letters.

For example, on the coin at the top left, I can see a letter "V" near the beginning of the obverse legend behind the emperor's head, the letters "NOBC" at the end of the inscription, and on the reverse "GLO RIAEXERC" is fairly clearly readable. I just typed in "V NOBC GLO RIAEXERC" and a whole bunch of coins of caesar Constans come up, like this one which matches your mintmark (DSIS - fourth officina of the Siscia mint).

The coin at top right appears to be a coin of Valentinian I - it appears to be a SECVRITAS REIPVBLICAE type with Victory walking like this one, but I can't see the reverse text clearly enough to be sure; I think the mintmark might be SMKA (Cyzicus mint), much the same as in the example I just gave.

The coin at the bottom is a FEL TEMP RPARATIO type with soldier spearing fallen horseman, similar to this one, but I can't identify the emperor. Mintmark looks like SMAN (Antioch mint).