Email Rocket Dollar's Customer Support team at firstname.lastname@example.org. Tell Support you'd like to make a contribution, including the year (you can typically make contributions for the prior year until you file your taxes), and the amount you wish to contribute.
Support will email you the contribution form. Support will also provide the buy direction letter to move the funds from the IRA to the LLC to the custodian. You will then send a wire or write a check to the custodian following the instructions on the contribution form. A few days after receiving your funds, the custodian will move the funds from your IRA to your LLC. Once the funds are in the LLC bank account, you can wire or write a check to make an investment.
For new contributions, do not send money directly into the LLC without first going through the IRA.