You're never going to have a manual for life. Even if you tried to go off someone else's notes, they wouldn't fit your exact situation, so throw them out. Know you're going to have to go forward without a map.
Life is about finding creative solutions. Einstein said "Creativity is intelligence having fun". When we allow ourselves to be creative with a problem, we inherently admit we don't know the answer. Allowing ourselves to explore solutions without needing to know the answer or be "right", allows us to let our guard down, we give ourselves some breathing room, we play.
All creativity has an element of play that is essential to its structure. Without the fluidity that comes from play, creativity is halted and squashed. Allowing yourself to play in a situation, whether it's giving yourself room to come up with various possibilities to solve a problem, or seeing an issue from other perspectives, or trying out new solutions, it's this sense of plasticity that gives creativity it's life force.
"Failing forward" is a term often used to describe the necessary steps needed to get to an end goal; many of which require failing at one thing or another in order to get to the next benchmark. Without that forward movement of falling down and getting up, falling down and trying it a new way, falling down and thinking of a different solution; without that process, the end result will rarely be achieved.
The most enlightened mathematicians, physicists, artists and musicians need to work things out; sometimes for decades. They can spend years on minor tweaks to calculations, formulas, etc, before getting to the end goal and even then, it's never "finished".
So next time you've failed, remember all the geniuses that came before you and all that they accomplished; pick yourself back up, and start again.