The
'techo' title above just means that in order to represent
larger numbers the Romans simply 'added' the symbols together.
e.g.
LXXXIII = 50 + 10 +
10 +10 + 1 + 1 + 1 = 83
Hints:

When writing roman numerals never use more than 3 of any
symbol.

When you have numerals on the right hand side of bigger
ones, ADD.
Have
a look at the examples on the parchment & see if you
can work out what is going on.
When
you think you've got it, try these:

Convert XVIII to our
number system
 Convert XXXVIII
to our number system
 What is LXI in our
number system?
 DCXXXII =
 MMVI =