Scubaseeker,
Congrats on purchasing your new Mares gear. You have a nice setup and as long as you maintain it and keep it clean you'll have years of enjoyable diving! To answer all your questions, I'd suggest you take it to your Local Dive Shop (LDS) and have a trained staff show you - that'd be easiest. But if you want to assemble your gear on your own it's not very difficult. I've attached a photo below. I'm assuming you have the MR42T or MR22T first stage regulator. If not, then your reg. will NOT look like my diagram and then I suggest you take it to your LDS to make sure you don't connect the hoses to the wrong ports.
But to answer your questions first:
1. The most common place people attach their Octopus 2nd stages are on the right side of their body somewhere in the area formed by an imaginary triangle between your chin and the bottom two corners of your rib cage. If you are referring to the metal D-rings on your Prestiage BCD on the right shoulder strap, that may be a bit too high. Do you have another mini plastic D-ring just above the RIGHT Pocket? I know there is one on the left side of this BCD above the pocket, but if you have one above the RIGHT pocket, yes, just buy a clip for your octopus (they make specially dedicated Octo holders) and attach it to that mini-plastic D-ring.
2. Your Proton Metal Reg. IS a good choice for cold water diving, however, it is absolutely perfect for warm water diving as well - esp out there in the hot sand box where you live! You have absolutely no worries. You chose a great reg, knowing that if ever you move to colder climates, your reg will be fine. You made a good choice.
Here is a pic for you on the basic assembly of your hoses. You just need an allan wrench and a typical crescent wrench and if you do have some SILICONE GREASE (NOT OIL!!!) you can lubricate the o-rings...but DON'T put too much silicone grease. Just a tiny bit is all you need. Use the allan wrench to unscrew the little port protector caps. Stow these in a safe place in case you need to plug them in at another time. Attach the hoses as per the diagram but make sure you don't tighten ANY of those hoses too tight. ie. Don't wrench them down so hard. Screw them in with your fingers until the o-ring disappears and seals and the metal from the hose housing touches the metal from the first stage and stops (finger tight). Then take your wrench and tighten it a bit more to make sure it doesn't come unscrewed accidentally. Your first stage has 4 LP (low pressure) ports and 2 HP (high pressure) ports. The HP ports are clearly marked as there are only 2 of them. BE SURE to only attach your SPG (console/gauge) to one of these HP ports. According to your info provided, you should leave the other HP port empty. Also, it is essential you attach your LP hoses on the sides as shown - as when you attach your unit to your tank, you will need these hoses to be on the 'correct' side. Here's a photo I made for you of the most common setup with a MR42/22T first stage (PM me with your personal email if you have problems viewing the photo and I'll email it to you). Remember, this is a picture of the MR42T or MR22T first stage. Don't follow these instructions if your first stage looks different:
According to the info you gave me, when your setup is complete, you should have one empty HP port and one empty LP port. If you still doubt yourself, to be sure, take your setup to any LDS and I'm sure they'll be happy to help you attach your hoses to your First Stage - most likely they shouldn't charge you as it takes just a few minutes! Again, it would be nice to know what exact model your first stage is. (Just FYI, the "T" stands for the special "Tri-material" Mares uses to construct the first stage valve.)
3. Your final question about your Mission console. I'm not quite sure what you are asking here. What exact console do you have? Does it have an integrated Mares Puck computer in it? Or is it just an analogue gauge (air pressure gauge/depth gauge/compass) console? Regardless, I don't know what software you are looking for. And also, none of these have anything to do with your Suunto D6 dive watch. They are entirely separate and will not communicate with each other. If you have a D6, the gauge will act as a backup in case your D6 fails. However, you do need the air pressure gauge on your console for all your dives. Please provide more information on what model console you have (eg. Mares Mission 1, 2, 2c, or 3 or Puck consoles etc.?)
I strongly recommend you visit an LDS after assembling your equipment to make sure you got it right. Good luck and happy diving!
Cheers,