Yes I went through as beginner too and I learn from somebody better. Split is completely fine but I'm sure you looking for optimal result right? The problem with split is you will be exercising each muscle group once per week. Compared to fullbody which target most of your major muscle group thrice per week. 1 time compared to 3 times. During beginner stage, your body doesn't need long recover period. Hence, frequency is more important than volume. It means that you just need to do about 3-4 sets for each muscle each workout day. And you hit the same muscles as frequent as possible and there's come fullbody routine.

And about choosing weight, it is suggested to use barbell instead of dumbbell due to the increment weight. For dumbbell, you need to jump from 7.5kg per hand to 10kg per hand and it means 5kg increment. Compared to barbell which has 2.5kg increment.It is easier to progress with barbell. And with some legit routine, you just pick a very light weight and you will progress to your max one day later. If you insist of doing your own routine and own weight progression, I'm sure you gonna use not more than 15kg for the same exercise that using 7.5kg now after 1 year as you don't know how to progress effectively.