Hello TheOrcadian
Can you say what help you need? What problems are you getting when you run this code? What is it doing, versus what you want it to do?
One thing to do is auto-format the code in the Arduino IDE (with CTRL-T). This will line up the indent levels correctly and show the structure of the program more clearly.
Something to check straight away is your 10 second timing while loop:
while((endtime - starttime) <= 10000)
Until either endtime or startime is updated, the comparison will always have the same answer. So you might want to check in what circumstances you update either of them
Lastly, you probably realise that when you get to each delay() instruction to flicker a particular LED, the program stops at that instruction until the delay is over. So you can only flicker one LED at a time with the way the program is designed.
This may meet your requirements. But if you need more things to happen at the same time, you should look at the "blink without delay" example program and use the technique it shows.
All the best
Ray