Setting up my equipment

Welcome and to answer your questions:

1. Cushioned flooring is a not a requirement. Boxing rings are generally cushioned somewhat with a canvas cover. If you want to simulate that, you may want to put down a cushioned floor of some type. Boxing shoes, if you wear them, will grip better on canvas covering and may be a bit "slippier" on a concrete or wood type floor. But if you're just starting out - no need to spend money on a cushioned floor.

2. Your bag weight - heavy bags usually have an inner and outer core. The inner core is filled with the materials which gives the bag weight and is then surrounded by an outer core just under the outer skin that provides padding. If your bag is too light, you can try and fill the inner core with a heavier material. Sand usually does a good job. If your bag has no inner core and is simply a bag - don't fill it with sand unless you put it in a waterproof membrane as it will eventually get wet and turn to concrete. Even in a bag or something it will eventually be very uncomfortable to hit. I've heard of people using pea gravel and so on to make it heavier. I'd suggest if you do have a bag with no core to make a core yourself out of some carpet tubing and surround it with old rags packed in real tight. You'll get the weight, padding, and it will feel comfortable.

3. I'm not familiar with your training gloves, but would suggest you learn to wrap your hands and then put them in the gloves. That way you'll be protected for sure. But to start, if you're not experiencing a lot of pain, bruising, scrapes, they're probably alright.