How do i cal and exe to run?

This is the bat (it is a txt cuz it wont let me upload a file with the bat extension) it is one line.

Good, now that we have the batch file I can tell you you don't need it. Just use:

nsExec::ExecToLog '"$TEMP\patch.exe" "$TEMP\simcity4-NA.RTP"'

NSIS can pass on command line arguments, you don't need no batch file for that. The above line should work.

It is working thank you so much

how do i launch a readme?

Use ExecShell. For example:

ExecShell open "$INSTDIR\readme.html"

If you are using the Modern UI read its readme there is a better way.