Specifically, what needs to be considered around parameters/features for choosing the right platform for beginners.
It depends which country you are from. It is best to not go to a deep discount brokers just because their commissions are the lowest.
For example, in US/Canada commissions for interactive brokers are the cheapest but that does not mean that you should actually use interactive brokers. It is just not meant for beginning traders.
In US/Canada commissions will range from 0.99$ per trader to $19.95 per trade.
If you choose some broker with around $5 commission per trade then their platform will be more user friendly then the ones with deep discount brokers.