This is an easy one (at least for me

)
You need to create two elementary files. So export as ProRes and it will export the whole video once your done with it with the HD ProRes file + 5.1 channel Linear PCM....now open compressor and drag the ProRes file....select "H.264 for Blu-ray disc" click on it and make any adjustments you need to....it automatically sets the frame rate and resolution as per your video but if you want to lower/increase the bit rate you can.
Now for surround sound. For surround sound Compressor doesn't feature all the proprietary and advanced codecs used on Blu-ray but you can convert to 5.1 Dolby Digital (Lossy) or 5.1 Linear PCM (Uncompressed). For Dolby Digital it should be under disc burning. It should be automatically be selected to 5.1 but click on it to make sure. Make sure its 5.1 with Low Frequency effects should be selected, dialog Norm should be -31dB's (for simplicity). Use Film Standard compression, everything else should be left alone as its set for the best experience. If you ever get serious about editing stuff be sure to check up on how Dolby Digital works and how to encode it...additionally other formats like DTS offer more options as well.
For 5.1 Linear PCM go down to audio formats and select WAVE. Make sure its set to 5.1 channels and not stereo or mono. For sample rate use 48000hz (48khz), thats the standard sample rate for movie audio (44.1khz is for music).
For bit depth I would select 24bit but 16bit will sound pretty much the same. Now send that off to the cue to be converted!
Alternatively you can use Handbrake with the latest build as it can decode and convert ProRes files now and its faster BUT you have to have a little more know-how. For example H.264 for Blu-ray does not allow more than 4 reference frames and some advanced settings as well so you have to be careful for compatibility. If you just select the AppleTV preset (which I believe is still there) it should be fine. Just make sure you go under audio and have the first track as AAC in Mono, stereo, or ProLogicII and the second track as 6-channel discrete AC-3 (5.1 Dolby Digital).
When its done download MkvToolNix/MKVmerge and you can add both files in and combine it as one .Mkv file to play in VLC player. VLC player will let you output multichannel audio. However you have to use HDMI or optical to be able to output the multichannel audio. HDMI can output both 5.1 Linear PCM and Dolby Digital but optical can only output Dolby Digital/DTS. For playing back on a Blu-ray player some players support .Mkv and .M2ts playback from a flash drive or standard data DVD and some don't, mine supports pretty much any format you throw at it in an .mkv or .m2ts format but you'll have to check in your manual either online or the hard copy.
For burning to a Blu-ray, Toast works but I don't like it because 1) After I've spent often hours waiting for Compressor to encode my file to the right standard and request Toast NOT to re-encode it still does it anyways, 2) When it re-encodes my files it does not use surround sound, in fact it only offers LPCM and Dolby Digital in stereo! What a load of crap! For burning what I do for burning to a 25gig BD-R disc is I add my files in TsmuxeR and select Blu-ray disk....I export the combined files and I get the entire Blu-ray disk structure and drag it to the blank Blu-ray disk in Finder and hit burn and it plays in all my drives....you won't get fancy menu's but you will get a disk that will play in anything.
If you have any questions just post back and Ill get back when I can (usually pretty fast). I do this stuff daily so its really not that much of a drag for me.
-Nate