Take your time. You don’t need to sit down and learn all of the multiplication facts at one time. In fact, this would be the worst way to learn. Choose a table and focus solely on that one. Take as much time as you need to master each one before moving onto the next one. Spend about 15-20 minutes each day studying flashcards or playing math games to master each multiplication fact. There are many multiplication math games with different themes that can be found online. For instance, if you really like dinosaurs, find one that uses dinosaurs to make learning more fun.
Children usually start to learn about decimals in Year 4. The first thing children need to know is that a decimal is A PART of a whole. A good way to explain this is to show them an empty hundred number square / chart.