Other tips: shoot-through umbrellas lead to lots of ambient spill light that scatters all over; this is worst in small shooting areas, and can be harnessed, or can ruin shots. Reflecting umbrellas with black backs keep the light moving,mostly, in one direction. Same with enclosed softboxes, and black-backed umbrellas boxes: the light is contained, and sent out in one direction, with fairly minimal spill light scattering around. Recessed face soft boxes, which have about a two-inch recessed face, allow you to control spill more than flush-faced modifiers do; if an egg-crate type fabric grid is added to a modifier, the grid accessory keeps the light moving only forward, and can keep light from spilling onto even nearby backdrops, or other pats of the shot. This si why so,so many newer softboxes offer an egg crate type grid as an accessory.
You can do a lot with one light. A 43 inch reflecting umbrella can light the person, and light the backdrop! A 28 x 28 inch gridded softbox from the same position can light the person, but make the backdrop go four stops darker. And this is why I suggest learning with one type of light unit, over several sessions. using the same main light source will give you a good idea of what it "does". This goes double if you are shooting blind, with speedlights, and can only evaluate your lighting placement and effects AFTER the shot has been captured.
The last suggestion: since you're using an APS-C camera, beware on half-body and 3/4 body shots like this, of getting into that 23 to 38mm focal length range from TOO CLOSE of a shooting range: this is a common issue with APS-C in-studio: the need to drop focal length to get a whole person in, and in the process, show too much background width behind the subject, and to show too much DOF at f/8 to f/11. If you have the room, it is almost always better to move BACK, and shoot with a longer focal length lens, or you risk running into background lighting issues. The short length lens shows more w i d t h of the background, behind the subject, than does the longer lens, with narrower FOV, from farther back. This becomes a big issue when you do not have lights that can cover a wide field of view BEHIND the subject. For a full-length person on APS-C with 85mm lens, you need to be 34 feet back; With a FF camera and the same,exact 85mm lens, you place the camera at precisely 20.0 feet for the SAME picture. But the backdrop is very different. Even though the person will be the same height, in an 8.5 foot tall frame. APS-C favors shooting from 7 feet back to 10 feet on singles, back to to 25 to 30 feet on larger groups.