Hey man, Yes you can use your universal remote for your Roku. First, you have to program it for your Roku TV. To program your universal remote to your Roku follow the simple steps given in the https://www.rokucodelink.com/
blogs. Roku.com/link is one of my favorite sites about the Roku Device which has a lot of blogs about the troubleshooting and setup and installation steps etc., you can also try this for your Roku troubleshooting techniques and queries. you can also get the proper customer support from the technical team also. Try it by yourself and you will know it.