If you want a decent job, youre going to need to get and/or make some things. YouTube is a great place to figure things out too. I highly suggest you take advantage of it.
Ive been making mostly sheaths, and some holsters, for a number of years now. After watching a number of videos on YouTube, I built a press very similar to Lost Woods' set up, and picked up kydex and the other needed parts/pieces from here.
https://www.knifekits.com/vcom/holster-making-materials-kydex-c-1071_54.html
Things youll want, kydex sheets, rivets of a couple sizes, a rivet tool that fit them, the kydex drill makes things a bit easier (its more precise and cuts a cleaner hole), but not really needed. For attachments, I usually keep it simple and use the rubber "pull the dot" belt loops you often see on IWB holsters, but they also have other attachment methods there as well and I believe they have some Molle stuff.
You can "score cut" the kydex with a straightedge and a sharp tipped knife (my preferred method), if you dont have a jig/scroll saw. Three or four passes with some heavy pressure, and you will get a clean "snap" when held over a sharp countertop edge and you press down.
The saws can be a big help if you have a lot of trimming after your done, but they can also screw things up pretty quick if youre not careful. I try to avoid any excess cutting after riveting.
A belt sander chucked into a bench vise at a comfortable angle works great, and actually better than the saw to finish (lets you shape and clean the edges up nice), as long as you dont have a whole lot to trim.
For a heat source, I just use the oven in the kitchen, with the kydex on a cookie sheet with a piece of tin foil on it. 350* for about 5-6 minutes seems to work best. You will want gloves, and everything set up and ready to go, before you put it in the oven. You dont have much time, once its out, and you have to work fast. If it sets up to fast, or you dont like it, you can put it back in the oven, and try again once it goes back flat.
I do have a small, torch burner that Ive used a couple of times to make "adjustments" to a few things, but thats not the norm. You have to be careful too, its easy to get carried away with a flame, and screw it up quick.
Ive heard people say they use a torch to warm the kydex sheets, but from what Ive seen, trying to do it with larger pieces, it doesnt work very well at all, and the kydex tends to get singed if youre not careful. The oven is the way to go.
As far as the molle mounts, I have a couple of knives on chest bags with Molle attachments. I use the pull the dot belt loops, as I find they are more versatile if you decide you want to take it off and use it elsewhere.
I slip the sheath behind something else mounted on the Molle, or even behind the chest bag itself, and slip the loop through the nearest attachment point on the rack. I find the knife is more secure this way, moves around less, and it also takes up less space.
These are a couple Ive done...