I can help.
Is this beam supporting multiple other beams?
So this is supporting rafters on one side only?
What is the rafter length?
Does this beam have rafters framing in on one side only or on both sides?
I'm sizing the beam now.
UB 203 x 133 x 25
203 mm tall x 133 mm wide
The designation provided is what you need.
It's an I beam as I stated above.
It's not too much if you want to limit the deflection to 10mm