Study tips for a normal week
Name the task before you start the timer, or the time will go on whatever happens to be open.
A named task is one you can picture finishing. Ten questions from the set, or the next section of a chapter. If the task has two parts, give them two sessions.
Reading goes better with a pencil in your hand. Mark a line you will want later, and write a few words in the margin about why it is there. If you reach the end of a page and cannot say what it was for, read it again before you move on. That second pass is slower, and it saves the evening you would spend trying to remember the page.
On a problem set, try the question before you look at the answer. Write a first step even when you think it is wrong. Then check. If it was wrong, find the step that broke and do another question like it while you still remember the correction.
Keep one place for the work. A desk is ideal, and a kitchen table is fine if that is the clear surface in the house. Leave the notes for this task within reach. Put other courses out of sight so they are not in front of you.
Before you stop for the day, write the first line of tomorrow's task on the same scrap of paper. The next session starts faster when you already know where to begin. The streak on this timer is only a mark that a session finished. Use it if a small daily mark helps you open the books. If a number would make a tired day feel heavier, you can ignore the count. A missed day sets the current streak back to zero, and the best mark stays.
If you have a choice, stop while you still know the next line, and write that line down. A late night can finish a piece of work, and the next day is usually worse for it.
The usual 25 minute pattern is written up in How the Pomodoro method works. The timer itself is on the home page. Pick a length that fits the task you named.