Note: I was pursuing a more technical role, like application developer, infrastructure or software engineer. This was considered desirable.
I received my first interview in mid-September. It was with two prior TECDP associates. They asked around 5-8 STAR, behavioral interview questions. They were very pleasant, sociable and patient. The experience ran a little over the hour allotted. I made sure to review my answers before the interview. A lot of the questions were the same as listed throughout the TECDP interview write-ups on Glassdoor. Review them. They hinted that I would be called for the second round.
A full month and a couple follow-up emails later (I sent a thank you, a two week, and one month follow-up to reinforce how much I wanted the position), I was informed I could participate in the Round 2 Day. Everything this year was virtual. I was given a few days to prepare 2-5 slides for a presentation on one of my projects. The R2D consisted of one behavioral interview (more STAR, ~half hour long), one easy whiteboarding session (I was allowed to use my IDE, the language of my choice, write pseudocode and use documentation), and the presentation (5 mins). The rest of the day was informational and social. It was ran by TECDP associates and the whole day had a social, laid-back feel.
I sent thank you emails to every person I interviewed with (5-6 people). Two week later I got a very competitive offer, which I accepted.