Start with the words
A repetition is one complete movement. A set is a group of repetitions. Resistance is the load your muscles work against. These words describe what you do; they do not tell you the right amount for your body.
Progress is a gradual change
Progressive resistance training means adjusting the challenge as your ability develops. That idea sits behind the training studied in the Cochrane review and the NSCA guidance for older adults.
Learning a movement and becoming more confident are useful beginnings. Continuing to develop strength also involves a suitable challenge. There is no single starting weight that works for everyone.
Make comparisons useful
An optional note about the exercise, resistance and repetitions can help you remember what you did. Compare like with like: a different exercise or a different movement range changes the task.
These are ways to understand a training plan, rather than a schedule for increasing your weights. A professional who knows your circumstances can help with that next step. Sturdy's introductory exercise pages do not prescribe sets, repetitions or progression.