Cooking pork belly slices?

[fasimew]

I've bought some supermarket pre-packaged pook belly slices and I'm going to attemp to cook it in the oven under the grill. Never cooked it before, so I need a few pointers.
What's a good marinade? I was thinking salt and chilli.
Is an hour long enough to marinate it?
What temp and how long should it go for?
How do I tell when it's done? I don't have a thermometer. I prefer my meat on the verge of being cooked, so it's still juicy and soft but safe enough to eat.

[fasimew]

Low and slow how? More info required.

I don't have an airfryer or slow cooker.

Those two methods sound interesting. Keep the ideas coming!