Volume is work done. This can be calculated as weight x reps x sets. Or, a more straightforward way to measure volume is to just track total sets. Intensity is how heavy the weight is relative to what you can lift.
Setting Realistic Fitness And Exercise Goals
Training Frequency
Do You Need To Count Calories To Lose Weight?
Calorie counting, and using something like MyFitnessPal, can be a very effective tool to manage your intake and induce weight loss.