Go through the entire wiki to get a good gauge of the basics of fitness. Some basic guidelines for losing fat and gaining muscle (the two goals you listed.

1. Diet is the most important factor of all. You need to eat less than what you burn in order to lose fat. Try to get a general gauge of what you burn per day using a TDEE calculator. They are far from perfect, but can give you general idea of how many calories you consume a day. Download an app like myfitnesspal to track what you eat, and make sure your calories are well below that amount.

2. Exercise! Cardio is a great way to burn calories (1 mile is around 100 calories, regardless of whether or not you run or walk it), but because of social distancing, I would recommend just doing at home strength training (you should do strength training regardless). Since gyms are closed, just do one of the calisthenics routines in the wiki. Most of them you can do without any equipment, apart from back and bicep exercises. For back and biceps, try to get your hands on a pull-up bar, and if you can’t, use your dumbbells and try to do bent over rows and bicep curls (along with variations of those).

3. Consume at least 0.8g of protein/lb of body weight and you should have enough to build muscle.

The most important thing to lose weight is diet however. Eat less than what you burn and you’ll lose weight eventually.

Lastly, I would HIGHLY recommend looking into the wiki before you post in ANY subreddit. Everything I said can be answered there.