I think there are no specific numbers in this case. You can start trading with any number you want. I started trading with a capital of 0.05B (50% of my total assets). At the beginning I only take profit 5% or stop loss 3%. After having experienced, I gradually raised the profit level and as now, when I have experience, the amount I use to trade is 0.5B
Yes, ideally you should start very small if you are new in crypto trading.
You have to familiarize yourself first and be comfortable of what you are doing.
In time, you will acquire strategies that will be of benefit when you are increasing your trading amount.
And also, if you will venture in other alts, it is better to study those alts beforehand so you have idea where the market is going.