Entry level newbie checking in.

Hey all. I guess my first post should be the obligatory check in... I'm no stranger to DIY stuff, it's just that the stuff I DIY tends to not turn out too refined. Oh, I can make things work most times, but they don't always work the best, or look the prettiest. Still, I try. I'm U.S. Army retired/disabled, but even though I don't work a real job, I stay busy being the Commander at my VFW. I'm building a 1980 Jeep CJ7 in the garage from the frame up. I'v build speakers before, but putting drivers, and crossovers into enclosures isn't hard.

My current project got me stumped, and I was directed here,So I signed up. My Bluetooth speaker is on it's deathbed. (Bose) It's had a good run, and sounded pretty good, but now it keeps losing contact with my phone, and shutting itself off. Pretty sure having somebody repair it will cost more that it's worth so I decided to try to build one of those ammo box units. I want to keep the cost down, living on VA disability and all, so I'l like to use off the shelf components, and even some leftover parts I have. Of course, I have ammo boxes. I ordered a battery, charger, bluetooth receiver. I have car stereo speakers, little sub, and an old amp leftover that I won't have to buy.

The plan may (probably will have to) change, but I'd like to use my little sub with this. It's a Memphis M Class 8" 15-MS84 I got for a vehicle I no longer own. I never did use it, and it has sat in the box in a cabinet in the garage for 4 or 5 years waiting... Here's the problem. I have an even older amp. It's a good one, an old Soundstream MC120, and I could run 2 channels for the 6.5s, then bridge the other 2 for the sub, but no crossover on new amps. Have to figure out how to either do a low pass, or use a leftover 3 way M B Quart crossover and just wire it in as the woofer.

Any tips on what section of the sight to search in, please throw them out. I'm having no luck looking around. This place seems a bit more advanced than what I will understand... Electronics, not my strong suit, but I'd like to learn...