What will be the best way to workout for me especially abs I use the total gym but its been a few months and I haven't really seen a diference
At 13y.o. you're still growing, so make sure your weights are not heavy to stress out your growing plates on your bones.
Simple pushups, sit=ups and chin ups will tone you up; and running will help you get back in shape. Don't forget to eat right foods so you stay healthy. Calcium and protein is very important since you are still growing.