How to buy Bitcoin and top Alts and transfer to Hardware Wallet

I know it may feel like such a noob and highly uneducated query, but it is as genuine as essential. I am currently accumulating crypto in Coinswitch app since early 2023 and will sell these around March, 2025 as there is no safety in holding crypto for long term on exchanges and that too Indian Exchanges.

So after selling all cryptos in bull run, i want to start investing in top cryptos later for long term. I tried hard to find the way/ exchanges through which i can buy crypto and transfer these to the hardware wallet, but i couldn't find a concrete way.

Can anyone please share step by step guide to understand on which exchange i should buy it and how. You can also share any link where it is available. Thanks in advance.