CNX is a proof of stake coin that has among its goals the ability for users to exchange any world currency for the cryptocurrency. Their roadmap also has plans for debit cards and integration with financial institutions.
While the ideas on their roadmap sound appealing they don't currently have a working product of any kind, and they aren't really doing anything that others have not already started doing, but better. At worst, a Cryptonex investment is wasted money on a possible scam coin. At best it's simply a mediocre pipe dream.
You can purchase Cryptonex on a relatively small number of exchanges. All of them are ones that I tend to avoid due to issues with how they are run. They have their own exchange which seems to show zero trade volume which is a red flag for me to stay away, but should you wish to buy some coins there is at least one option with some trading volume. They also have an option to purchase it from them directly, but the process seems very shady.
If you need a place to store your CNX tokens you can use their desktop wallets for Linux, Mac or Windows. They do not currently have a mobile wallet available. Keeping coins on any exchange but especially the ones this asset is listed on is not advisable. Many smaller exchanges have a habit of going down without warning, and if they do you very well may never see your money again. If you do need to use one of these exchanges; purchase your coins, and then immediately transfer them to a safe wallet in your possession.