I got an R50 years ago, and have now switched my TV to the TCL S405. Apparently the R50 does not have codes for it. I've been trying to re-learn how to set up this remote, searching and reading. The only thing I could find was this post here:
"closing this thread out, the TCL code set in URC library for model "55US57" worked perfectly for this Roku TV model."

I'm unable to find this "code library", or how to input the code. could anyone help me out?

Try tv codes listed under Goldstar, LG, or RCA.

55US57 is setup # 749. See if that code is is listed in your TV database in the remote.

I tried Goldstar, LG, and RCA, no luck there.
The only way I can find to get to #749, is to add a TV, then scan
all codes. I did not see anything close to #749.
I guess mine was produced before that TCL 55US57 was
added to the database. Sure wish I could update the remote.
I guess these "roku tvs" are less than optimal for setting up
one of these remotes? Thanks for the input!

EDIT: I read what I could find till I remembered most of what
I needed to do to set up the RC50. Just went with learned
commands and macros.

In the future, try code 096. It might be under Dynex or Emerson.