Advanced Frog Stand
Then start working on the pushup
You should be able to hold for 60 seconds, each progression, before moving on to the next.
Train 3 times per week..Each progression hold a cumulative of 60 seconds until finally you get 60 seconds.
I have seen 220 lb males do planche pushups. SO don't fear.
Coach Sommer has an excellent book on it just out - don't buy the videos. They are not worth it. The book has everything you need.