Verifying a Contract on BSCScan.com - solidity

Question

I created a cryptocurrency with the help of a friend of mine (it took us ages to copy-paste codes from here and there) and to edit the contract's info, which is crucial for me, I now need to verify the contract. Here's my contract address:
0xe1c7a0d5e099a1f0c14b60b0c320423cf2f4543b
and here is the code I used in Remix:
pragma solidity >=0.8.0;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol";
contract HelpingArtistsAtRisk is ERC20 {
constructor(uint256 initialsupply) public ERC20 ("Helping Artists At Risk", "HAAR"){
_mint(msg.sender,initialsupply);}
}
It gives me error after error when I try to verify it. Here are the error messages:
Warning: SPDX license identifier not provided in source file. Before publishing, consider adding a comment containing "SPDX-License-Identifier: " to each source file. Use "SPDX-License-Identifier: UNLICENSED" for non-open-source code. Please see https://spdx.org for more information.
--> myc
ParserError: Source "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol" not found: File import callback not supported
--> myc:3:1:
|
3 | import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol"
BEP-20.sol:1:1: Error: Compiler version >=0.8.0 does not satisfy the r semver requirement
ParserError: Expected pragma, import directive or contract/interface/library/struct/enum/constant/function definition.
--> myc:1:1:
|
1 | "SPDX-License-Identifier: UNLICENSED"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I just wanted to have the BSCSCAN's verification.

Answer 1

Since solidity 0.6.8 you should set a License header to your contract, so you need to add this at the first line of your file:
// SPDX-License-Identifier: UNLICENSED
You can use the UNLICENSED or use one of the predefined licenses. Here is the list: https://spdx.org/licenses/
More information about the SPDX License herader here: https://forum.openzeppelin.com/t/solidity-0-6-8-introduces-spdx-license-identifiers/2859
This should fix your first Warning and the last error.
After making this change I was able to compile the contract using remix, but I think that all other errors are related with the compiler version, could you share version and other settings that you see in the compiler options?
I'm using Compiler 0.8.4+commit.c7e474f2
Also you need to remove the public keyword in the constructor, it is ignored by the compiler. The final result is:
// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.0;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol";
contract HelpingArtistsAtRisk is ERC20 {
constructor(uint256 initialsupply) ERC20 ("Helping Artists At Risk", "HAAR"){
_mint(msg.sender,initialsupply);}
}