How can I redeem my free GTA San Andreas?

The announcement states:

Download Now and get a bonus FREE copy of Grand Theft Auto: San Andreas on PC for a limited time

This was posted September 17, 2019. In all probability the giveaway has expired.

Another announcement states the offer ended on October 8th 2019.

For those yet to download the Rockstar Games Launcher, be sure to download by Tuesday October 8th to get Grand Theft Auto: San Andreas for free.