My bother got me a copy of trs19 platinum edition. I tried to install it But it would not take my user name or pass word. Plus it doze not show up in my digital downloads. Could someone help out here with this. Thanks
Ouch! It will be registered to whatever account / username he set up to purchase it with, you can't gift it to someone else as it's locked to the username that purchased it.
Since it was purchased under his username, it'll only work under his account and won't work for others.
Also since it was already purchased under his account, he'll have to contact the helpdesk https://support.trainzportal.com/ and request it to be transferred over to your account.