The most important thing in strength training is progression. You need to progress as well as you can in each training session to effectively build muscle and strength in the long run.
One of the best-known and best methods is the so-called double progression. This method is a time-tested approach, first mentioned in 1911 by weightlifter Alan Calvert.
With the double progression, you combine changes in the number of repetitions with changes in the weight to realistically increase the weight in the long run without large fluctuations of the underlying 10RM or 1RM.
With double progression, you set a specific repetition range per exercise in which you train. So you perform your reps in a set range of, e.g., 4-6 or 8-12 reps.
As soon as you reach the upper end of your repetition range for an exercise with a certain weight, you increase the weight to the next higher weight in the following training session. With this weight, you complete as many repetitions as you need to reach the lower end of the repetition range.
For the underlying 10RM or 1RM to increase as constantly as possible, it is essential to adapt the repetition ranges to the available weight intervals of the exercises.
Choosing large repetition ranges for exercises with large percentage weight intervals would be best. An example of this is the lateral raise. For example, if you train with a weight of 10 kg and the next higher weight would be 12.5 kg, this would be a percentage weight jump of 25%.
This is very unrealistic to achieve without a significant drop in repetitions. For this reason, you should choose a large repetition range of, e.g., 10-20 reps for such exercises.
Choosing small or no repetition ranges for exercises with small percentage weight intervals would be best. An example of this is the Leg Press. For example, if you train with a weight of 200 kg and the next higher weight would be 202.5 kg, this would only be a percentage weight jump of 1.25%.
This is realistic to achieve without a (significant) drop in repetitions. Consequently, you can increase the weight here with a constant number of reps or use only a tiny repetition range of, e.g., 8-10.
The progression recommendations of the Alpha Progression app are based on double progression. So you can easily use double progression to build muscle and steadily get stronger.