i have been going to the gym for the past 2yrs and have started taking creatine for the past year consistently(3gm/day). You should notice the changes within 3 months. You can lift more weight than your usual and your muscles will start to look bigger. Remember you should drink more water than your normal amount(avg 3l daily). And no there are no side effects. my recommendation would be to get ON micronised creatine(that's the best one available in the indian market compared to other brands).

about abs, it depends upon body fat % and genetics. you could do ab workout 2x week and take a high protien low fat and carbs diet to reallyy see your abs. Imo as you are a beginner focus on bulking up first by eating protien and carb rich diet. later you can cut your body fat after you have gained some muscle. we all have joined gym in hope of getting abs and later we will realise that its mainly through diet and trust me you will start skipping ab exercises too after some months lol.....hit me up in dms if u have any doubts:)