Application with Ethereum Smart Contracts [требует правки]

I need to create ios,android,web application which must interact with Ethereum blockchain. Application will have users. The main idea that users will interact by doing special activities, for which they will receive tokens with the help of Ethereum smart contract.

Example: In application user1 sends user2 test about product.If user2 answers questions in this test he passes this test and receives 20 tokens. This operation must be done with Ethereum smart contract.

What is the scheme concept / architecture for such application ? For example: Client application(user) --> html,css,web3js --> Back-End+Database--> Ethereum Virtual Machine. I guess i need to have classic client-server app but with connection to Ethereum Blockchain.

Please dont judge me I am not technician(!!!

How users will create from my application Ethereum wallet address to send and receive tokens ?

Where the private keys of this wallet addresses will be located ? Locally ? How to secure from breaches?

What technologies must be used to implement interaction with Ethereum blockchain and where ? I found this - Geth,web3js,Metamask,Meteor,testrpc,Ethereum web3. Help me to structure them logically ?

Any examples of such applications to look at ? I found none. Maybe you can advise something ?

I have spent hours googling,have chaos in my hand. I am business manager,not technician but I want to understand this questions.

Would be very appreciative if you can drop me come clues to have understanding.

What info helped me to get minimal understanding :

https://ethereum.stackexchange.com/questions/12936/executing-a-smart-contract-in-a-mobile-app

https://medium.com/zeonlab-blockchain-semantic-blog/interaction-with-solidity-using-web3-5a4f1a7166f3