I've got a Trane xe 80 furnace model #TUD100C948JO. I got a new transformer and not understanding wireing schematic can someone help me please.

The transformer should be labeled. Most are 240,208 or120 VAC in and 120 out depending on the use. Some have 24 out for relays and thermostat. Using the schematic you would have 2 in and 2 out, capping off the unused leads. How was the old one wired?