Need help understanding TDK

I am 57 yr old male and have been on Keto for 6 months and have lost 20 lbs. having previously lost 35 these were "hard to get off" pounds. I went from 240 to 218, then started Keto and dropped down to 195. I workout 4 days a week mostly intense weight training. I have heard about TDK (I believe it's called) and I'm interested in putting on more muscle. I believe it entails consuming a set amount of extra carbs prior to workout, not sure the best way to go about the carb load and stay in keto. Any help?