This is a very good program if you are happy to increase your max by 2.5 kg per month. This may not sound much but I can promise you that when you have trained for some years, this is more than most can hope for.
Week 1: 2 reps x 6 sets at 80% of 1RM
Week 2: 3 reps x 6 sets at 80% of 1RM
Week 3: 4 reps x 6 sets at 80% of 1RM
Week 4: work up to 1 rep at 90% of 1RM
Assume that your 1RM has increased 2.5 kg and calculate your weight for the next month. With this program you will increase your max of 30kg in a year if you do not get impatient and change programs.
