Hi,
In order to download the **firstdayofmonth** Xtra Function and to use it in the **ITPilot**, I would follow the below steps:
* Log in to the [**Denodo Support site**](https://support.denodo.com/) with a user having a valid Support access.
* Navigate to Downloads > DenodoConnects > Denodo Xtrafuncs for ITP > **Download**.
* Check the [**Adding Extensions**](https://community.denodo.com/docs/html/browse/8.0/en/itpilot/generation_environment/generation_envirtonment_tools_-_part_ii/managing_extensions/adding_extensions#adding-extensions) documentation of the ITPilot and choose the **denodo-xtrafuncs-itp-date-8.0-<version>-jar-with-dependencies.jar** file from denodo-xtrafuncs-itp-8.0-<version>/dist folder and import as a ITPilot custom function.
By performing the above steps, the “firstdayofmonth” Xtra function can be used/availed without any hassle.
To know more about the **firstdayofmonth** function, you can refer to the [**Denodo XtraFuncs**](https://community.denodo.com/docs/html/document/denodoconnects/8.0/en/Denodo%20XtraFuncs%20-%20User%20Manual#:~:text=52%20PDT%202018-,firstdayofmonth) User Manual.
Otherwise, if the need is to use this function in the Virtual DataPort of the **Denodo Platform 8.0**, then be informed that it is not necessary to import manually, whereas the **firstdayofmonth** function comes as a built-in function.
You can have a look at the section [**Datetime Functions**](https://community.denodo.com/docs/html/document/denodoconnects/8.0/en/Denodo%20XtraFuncs%20-%20User%20Manual#h.g1ojo3imkiov) of the Virtual DataPort VQL Guide for more information.
Hope this helps!