new to djing and try first transition

just record transition part only
https://youtube.com/watch?v=oposDNwHmk8&si=sHfrvUW39PY6kwPR
i tried fist transition... but not satisfied....
i learn simple basic in vr, like how to control...
anyway what i wondering now is when to go into the new music, how long to bring them together, and at which part to exit.
and about selecting next music for transition

i can split phrase but i havent found my own clear rationale about transition
what should i learn first? i check lecture list of crossfader, club ready dj school online course and youtube playlist, but still dont know what should i do first.
i want something like theory

always welcome if you have any feedback about transition or answer about question

music a : https://www.youtube.com/watch?v=qCXGIct-G88
music b : https://www.youtube.com/watch?v=dS9WirONly0