do it again tomorrow, then next week, etc…
but it doesn’t matter if you forget how to solve one specific challenge, you are improving your problem solving skills, with time you will find that there are common patterns in algorithms
and if it is instead an issue of syntax, just use google every time you have doubts on what something does or on how to write something.
googling, consulting documentation often (from multiple times per day to multiple times per hour) it is totally a normal thing
Build something(s)! Practice by exercise and discipline is good, but practice while building a full solution/app it’s awesome. Your acquired knowledge and skills will be cemented into your mind by building actual infrastructure (networks) in your brain. Plus building something is fun and rewarding!
Just like ieahleen said:
And take notes and talk about what you’ve learned etc.