I will shed some light below:
If you sell TSLA shares after the record date of Aug. 21 for TSLA but before Aug. 31, you will sell them at the pre-split price. You will not be entitled to the split shares. For example: If on the last business day of trading TSLA, Aug. 28 you sell 100 TSLA shares for a pre-split market price of $1,600 per share you will receive $160,000. You will not receive any split shares.
If you buy TSLA shares after the record dates but before Aug. 31, you will purchase shares at the pre-split price. Following the split, you will receive the additional shares resulting from the stock split. For example: If on Aug. 26 you buy 100 shares (and hold them through the open on Aug. 31) at $1,600 per share, you will pay $160,000. You will receive 400 additional shares after the stock split, and the price will be reduced to the post-split price.
In a nutshell, the price will be divided by 5 on the 31st of August. If you are holding the stock before that (28th of August) you are eligible for split shares.