Approve and Transfer ERC20 Tokens in contract

Question

I'm pretty new to solidity and struggling with some pretty simple stuff so I was hoping somebody would be able to help me out. Basically, I want to be able to send an existing ERC20 token (ie: USDT) to a contract. I think I understand that you have to approve the funds then initiate the transfer.

function fund(address sender, uint256 amount) public {
        IERC20(i_assetAddress).approve(address(this), amount);
        IERC20(i_assetAddress).transferFrom(sender, address(this), amount);
        s_funders[sender] = amount;
}

I set the address to the USDT contract address: 0xC2C527C0CACF457746Bd31B2a698Fe89de2b6d49 and ensured that my deploying account had enough funds in it to make the transfer. No matter which ways I tweak it I am always getting the same error on the transaction when I run the fund() function: Fail with error 'ERC20: transfer amount exceeds balance'. I know I'm definitely pretty off-base so hopefully someone can help me figure this out. Here's the relevant typescript code in my testing function:

describe("FundMe Staging Tests", function () {
          let accounts: SignerWithAddress[], deployer: SignerWithAddress, user: SignerWithAddress
          const fundValue: BigNumber = ethers.utils.parseEther("0.00001")
          let fundMeContract: FundMe, fundMe: FundMe
          const chainId = network.config.chainId || 31337

          beforeEach(async () => {
              accounts = await ethers.getSigners()
              deployer = accounts[0]
              console.log(deployer.address)

              fundMeContract = await ethers.getContract("FundMe", deployer)

              fundMe = fundMeContract.connect(deployer)
          })

          it("correctly adds a funder", async function () {
              fundMe = fundMeContract.connect(deployer)

              await fundMe.fund(deployer.address, fundValue)
              const fundAmount = await FundMe.getFundAmount(deployer.address)

              console.log(`fundAmount: ${fundAmount} | fundValue: ${fundValue}`)
              assert.equal(fundAmount.toString(), fundValue.toString())
          })
      })