Here is the step-by-step guide based on the workflow you explained. I have left the specific prompts and link buttons blank so you can fill them in, just as requested.
Step-by-Step Guide:
Step 1: click two pick one of bike key then the bike photo
step 2: copy this prompt
Prompt :-
Step 3 go to google flow then add freme to video model then add both images then phaste the prompt