You will need a wallet that support many coins, in this case you may go for trust wallet
Trust wallet is closed source, so not a good source of privacy or security. You should be looking towards an open source, multi coin wallet, here's a
list of such wallets.
1. Do i do the same and open various wallets and buy the coins that way or do I have to use an exchange like Coinbase or Binance to buy the coins?
2. If/when I want to sell the coins do i withdraw via the wallets or do i go onto an exchange and sell? Then transfer the money to my bank account.
3. Is there a secure wallet I can get with can hold all the coins in 1 place or do i have to open multiple wallets?
• You do not buy and store coins on the same platform, the above linked list contains open sourced option for wallets. There are decentralized exchanges you can use to buy.
• Depends on what platform you're selling on. If it's a P2P wallet, you need to integrate your wallet onto the platform. For. Centralized exchanges you send to your account and then sell.
• I have not used enough multi coin wallet to give a suggestion on that.