What is the time frame to enter Thailand after the approval of a DTV visa?

I have enrolled in a cooking course and will not be arriving until November. I have applied and already received my DTV. My letter of enrollment which states the course start month as November was supplied to immigration at the time of application. You can enter at any time within the 5 years. No time limit for travel from when you get your DTV approved.

Enter anytime within the 5 years

The visa is valid for 5 years from the time of issue but I'd not apply earlier than 3 months from the date of travel you supply

There does not seem to be an "enter by…" date.

This is entirely different from Vietnam visa which has a limited entry/exit period on the visa.

Once the DTV is approved, you have 5 years time from the day of approval to enter Thailand. The validity of the visa is also stated on the PDF that you receive from the consulate.