Start from the beginning. You need an Operator Manual. The one for YM240 is close enough if you can't get one that is specific to YM1700.
'Oil Change' usually means the engine oil, not the transmission. The modern recommendation for the engine is diesel-rated oil, in 15w40 weight. Buy a gallon jug.
Any top brand is recommended (I use Delo) but synthetic isn't needed. That will fill it to the halfway point or more on the dipstick.
For the oil filter, #1334 or #1064. (Individual brands will put their own prefixes ahead of these digits.) Ask for the most widely used Honda oil filter. It should have one of these numbers on it.
The transmission is completely separate. Yanmar specifies 'John Deere 303 equivalent or better' tractor/hydraulic fluid. Buy a 5 gallon pail and expect to use about 4 gallons. (I use Coastal, the cheap generic brand from Autozone.) But before you change it, arrange where to get a replacement transmission filter screen in case the old one cannot be reused. Note that the hydraulics that lift the 3-point linkage in the back also run off the transmission fluid reservoir. If the hydraulics work properly, you don't need to replace the hydraulic fluid immediately before using the tractor.
Back to my main point - get a manual to become familiar with what your tractor needs.
You might like to look at the brochure for the American version of your tractor, referenced in my sig file below.
And welcome here! You will love your Yanmar, as we all do!