Using Keyboard Shortcuts in BetterTouchTool to Simulate a Press and Hold Left Mouse Action with F1

Hi everyone,
I'm newbie in BTT. Hope to receive your help.

I would like to use Keyboard Shortcuts in BetterTouchTool to simulate pressing and hold left mouse when I press F1, only releases when I press F1 in the second time.

Please suggest the way to do. If you can have a screenshot for the set-up, please let me know as well.

Thank you so much

Use a cycle action with custom click (or whatever it's called in English)

F1: left click and hold
F1 again: release

Thanks for yout support. Could you please provide the screenshot for this setting.

I appreciate it. Thank you so much