When and How to incorporate strength training

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Hey! I'm a newbie been joined for almost a week now. My exercise routine consists of an hour in the morning on a stationary bike at a general pace and either 30 more minutes at night or walking a mile on treadmil at 2.8 mph. So the cardio is covered. I get it and it's pretty much fool proof. My goal is to lose 75lbs and more. So basically how do I add strength training into my routine? How often? And also a simple idea for a beginning plan. I want to tone my body at the same time when losing weight. I'm 23 and ready to look 23! Help plz :)