7 Y/O, no exercise routine, trying to gain a bit of advice. Tips and advice?

*17 Y/O

Copy pasted from r/fitness, to exaggerate how lazy I am. I get called a "stick" often, so I want that to change.

I stopped sports last year, and about 6 months ago I started casually weighing myself before showers, and my weight started to go from about 58KG (128Lbs) down to 57KG (126Lbs) and so I started to just eat a bit more, going up to about 59.7-60.2 in the last week. What kind of exercises should I be doing? I have absolutely no muscle tone, where should I be starting? I have a weight machine (http://www.getholistichealth.com/wp-content/uploads/2013/01/3378854_2-225x300.jpg [1] - the pully thing and feet thing on that) (http://www.howefit.ca/wp-content/uploads/2014/04/legcrusherlegs.jpg [2] - one of those things) and (http://www.phoenixrevolution.net/wp-content/uploads/2010/05/legextension.jpg [3] ) one of those, with 2 5KG dumbells I think they're called. What should I be doing? Running, exercising? Any help would be great, I've tried googling things and going through the wiki, but some sources seem to be telling me to run and others telling me not to run and to be doing heavy weights rather than a bunch of light things, and it's all quite confusing. A few years ago, I also had baby fat that all collected in my face, and that was a time where I was ashamed of the way I looked - I'd never want to go back to being fat faced and never want to be overweight.