Whether you've lost the instructions for your Toshiba CT-90159 remote, or need some extra help with the remote's programming, there are lots of places online which can help.
To start with, you can download a copy of the manual in PDF format at tv.manualsonline.com/manuals.
replacementremotes.com/TOSHIBA offers a mail service if you'd prefer a hardcopy sent to your home, though they do charge a small fee for this service.
If you still need a hand operating the remote, you can look in on one of the home appliance online forums such as fixya.com, which has a thread dedicated to the Toshiba CT-90159 remote.
Lastly, you can seek help from Toshiba themselves, via their product support or community forum, which you can access here.