I'll look into the forum later but I'm wondering how hard this is to learn and how good the reception inside a house would be.
I want to make a clarification to my first post - you do not need a Raspberry PI. You can use a windows computer with at least a i3 CPU running a Linux virtual emulation package to control the SDR dongle and run OP25.
Reception inside the house depends upon how well the SDR and antenna will pickup the control channel(s) from the system you want to listen to. One SDR per system - you can successfully run 2 NooElec NESDR SDR's on a 4Gb Pi4 using a good power supply. They do get warm!
If you have digital scanners that pickup DTRS, you should have no issue using the SDR. The NESDR is a rock solid design with temperature compensation built in to avoid drifting off the control channel. The OP25 github package uses a digital voice codec module that is just as good as any commercial scanner. The OP25 package comes with a web interface to fine tune the SDR to center control channel frequency, show details about the control channel site configuration, talk groups using that site.
I noticed a lot of the streaming audio sites are using this solution.
How hard is it to learn? - To quote a fellow scanner hobbyist "There is a fine line between 'hobby' and 'mental illness'." If you are not familiar with SDR's, intimidated by installing and running Linux, using shell command line scripts, tweaking OP25 command line options, then there will be a learning curve. The SDR, OP25 forums and wiki here are a good start.