How and what platforms should I use to buy stocks worldwide?

I use both Interactive Brokers and Thinkorswim. TOS for the better rates but IB for the variety of countries!

I would also suggest you stick with interactive brokers mainly because its the best brokerage fee to an individual invester out there.

However, if you're concerned about minimums, I would say you can do saxo because if the volume is very low, it would still make sense to do it

I am using SCB for all! But you would have to top up your account first, so it's not like the typical CDP brokerages in Singapore.

If you are not a frequent day/swing trader, and planning to hold stocks long-term and rcvd dividends, SCB would be a consideration. No custodian fees and dividend handling charges