1. Read to your child a lot.
2. When you read to them or when they read by themselves, ask them to express what they just read.
3. Discuss what they read by asking whether X should have done Y.
Of course, you’ll need to weave phonics in there as well.
Do this, and you will lift reading from a mechanical process to a personal experience. You will succeed.
By the way, if you want to stop forgetting everything you read, the key is attention, which is an assertion of the will. After you read something, pause and recount what you just read. If you don’t have time to do that, you are probably wasting your time reading and indulging yourself anyway.