I have been vegan since 2010. So far, all my training has been cardio (running, pretty much). Now I would like to also build up some upper body strength and lose fat. Mainly, I would like to focus on my arms and chest (building muscle) as well as my stomach (lose fat). I would also like to tighten my stomach, if possible. Even when I was on my lowest weight ever, my stomach has been hanging down. I am a 29 year old male, 186cm, currently around 78 kg.
Ideally, I would just do some body weight exorcizes rather than going to a gym. Can I achieve my goals this way? Alternatively, I have considered buying equipment to use at home (rowing machine or one of those all-in-one weight lifting stations).
I do not have any problems with cardio. Walking 20k or running around 12k is fine; however, working out to build muscle seems to be pretty tough on me. I did go to a gym for a month, which was just not for me. I have pretty much _no_ upper body strength, so I have to start at zero.
What kind of excercize (and possibly diet?) would you recommend for me to achieve my goals? Which, again, pretty much are: getting in shape (less fat, especially stomach, more muscle, especially arms and chest).
In the past, I have always just focused on losing weight. I ate less and ran more. But this time I’d like to really make a change. Another problem is that I have pretty bad posture. Whenever I realize this, I try to improve it but is there a certain exercise (or tool, like a back brace) you can recommend for me to permanently achieve better posture?
Thanks in advance

Cheers!