Well because i dont have a clue of what ruler it is, not even what it says on the mint mark 
So i am guessing it's constantius ii with the mint mark smkepsilon?
That is the glory of the spreadsheets. Start putting in things you know and see where it leads.
For this example, surely you know the
reverse type is the fallen horseman, FEL TEMP so you load up that spreadsheet.
What can you say for sure?
Mint mark ends in
, well now you have been around long enough to know it is
Cyzicus, so you plug it in to the spreadsheet, now 5 possible emperors becomes 4.
Next, surely you can see that the
bust type isn't a bald
head or a rosette diadem, so the only thing left is
PDC (pearl draped
cuirassed), you plug it in to the sheets and BOOM, you are down to 2 emperors.
Now, the list is small, you look at the
mint marks and see there are only two
mint marks with
officina , you have
SMK
and
SMK and in the blink of an eye the only emperor left is
Constantius IINow, maybe you can see a
field mark, or maybe you can decipher a particular horseman
type, or maybe there is an obvious
legend break, all pieces of the puzzle that eventually get you to the promised land.
Next thing you know you will be helping new
LRB collectors attribute their coins
