As @abhi1017 has commented your formula is not quite right regarding the syntax. Rather than writing the module and line references manually select them directly and the correct references will pull into the formula automatically.
Also, are the dimensions of the source are present in the target module. IF so, then you can simply reference the data and it will populate from source to target. However, if there is a difference in dimensions you will receive a mismatch of dimension error. If this happens you will need to map your source dimensions into your target module.
It would also be best practice to simply reference the source directly in any downstream formulas as you are creating redundancy by duplicating the start date and any other property in your target module.
Chris Heathcote Bedford Consulting
Gold Partner and Regional Partner of the Year 2021, EMEA