How does the full lifecycle of a cryptocurrency trading look like?
Depending on where you live there are different options. I would suggest, if in the US, to go with one of the larger platforms like Kraken.com, or CoinBase.com. In these systems you can wire funds (Kraken) or attach to a bank account to purchase currency. 

In my experience, CoinBase will be your training wheels. It's hard to see what you're buying/selling as the actual transaction occurs automatically when you click the button. What you see is not what you'll get (unless that changed in the last week). However it is very easy to use.

Kraken will require more verification for additional tiers (work with more value). But you can control the trading. You can set buy/sell limits which means you won't get 1 penny less than what you told it. They have tons of additional trading options if you want to get more advanced as well. 

Final note, Kraken supports many more crypto currency options and bought cryptowat.ch over a year ago for a nice live feed of prices across multiple platforms.

Hope this helps you get started!

Edit: I'm not here to judge intentions or viability. The question was  "what can i use". Any assumption (including commentary on the current market, political, legal, etc) other than "I'm simply answering the question" would be incorrect.