welcome to the forum moonstarter; not entirely clear what you have done; so if I work through things, and you can confirm things;
so you opted for the Brother installer tool; which should be a good idea;
it comes down as linux-brprinter-installer-2.0.0-1.gz
from the page http://support.brother.com/g/b/download ... &type3=625
it would seem the commands would be:cd Downloads
(assuming one downloaded the file to this directory and saved it there)gunzip linux-brprinter-installer-2.0.0-1.gzsudo bash linux-brprinter-installer-2.0.0-1 HL-2135W
then Brother say
When you see the message "Will you specify the DeviceURI ?", For USB Users: Choose N(No)
.............so we are assuming you have a standalone computer with printer connected by usb cable: correct assumption?
if you use the UP arrow from your keyboard; when the terminal is open; you can go back and see the history of the commands you used: can you confirm the above commands please?
and to check what was installed can you copy and paste this command into a terminal please
dpkg -l | grep Brother
and copy and paste back what you get please
and if you click on this link http://localhost:631/printers/
it should open CUPS (printer control) in a web browser page but it is only looking on your system
......is the HL-2135W listed there; I enclose a snapshot below of what our MG3100 setting looks like; On looking to see what files are needed......from a link I used to have to the Brother site......seems to me Brother have had a big backroom tidy-up: one can no longer find the individual lpr and cupswrapper packages: Brother have standardised on using the script: so one can only use the script these days