Here is a demo that I believe covers the basics of your initial request:
Arrow_KeyFrame_JHSv1.hype.zip (28.4 KB)
Online Demo here.
• "Left/Right" arrow keys (i.e. prev & next) jump to programed keyframes.
• "Down" arrow key triggers "continue timeline" from that location.
You can use both the "keyframe" & "continue timeline" key strokes together...
e.g. jump to a keyframe and then continue the timeline from that location.
There is one function called "arrowKeyFrame" that does the work.
This function is triggered by "On Scene Load" ("Scene Inspector").
All You need to do is fill in the keyframe times for your project in the very first line of this function, between the brackets [ ] ... don't forget the commas as the value separators.
keyFrameTimes = [0, 2, 3, 6];
// array - put your keyframe timeline values (in seconds) between the brackets
Read more about "arrays" here.
Also the timeline being referenced in this function is the "Main Timeline" - You will need to change each instance (4 total) if You are using another timeline.
Important Note: This demo is not intended to be bullet proof... there may be adjustments needed depending on your circumstances... so consider this as an example along the lines of your request.
Below is another file that is structured to be a little easier to read~follow. It has the exact same features and is thoroughly annotated. The "arrowKeyFrame" function is triggered by "On Key Down" ("Scene Inspector").
Arrow_KeyFrame_JHSv2.hype.zip (28.5 KB)